Methods and compositions for diagnosis and treatment of cancer

ABSTRACT

The present invention relates to the identification of nucleic acid and amino acid sequences that are characteristic of colorectal, in particular colonic, and gastric tumor tissues and colorectal, in particular colonic, and gastric tissues, and which represent targets for therapy or diagnosis of such tumor diseases in a subject.

Gastrointestinal cancer (cancer of the digestive system) includescancers of the esophagus, gallbladder, liver, pancreas, stomach, smallintestine, large intestine (colon) and rectum. Some form ofgastrointestinal cancer amounts to about 20 percent of all newlydiagnosed cancers every year.

Colorectal cancer includes cancerous growths in the colon, rectum andappendix. It is the third most common form of cancer and the secondleading cause of cancer-related death in the Western world. Together,colon and rectal cancers account for 10% of cancers in men and 11% ofcancers in women. It is the second most common site-specific canceraffecting both men and women. Many colorectal cancers are thought toarise from adenomatous polyps in the colon. These mushroom-like growthsare usually benign, but some may develop into cancer over time.Colorectal carcinoma often presents as metastatic disease that impedescurative surgery. Over 20% of patients present with metastatic (stage1V) colorectal cancer at the time of diagnosis, and up to 25% of thisgroup will have isolated liver metastasis that is potentiallyresectable.

Cancer of the colon or colon cancer is a disease characterized by thedevelopment of malignant cells in the lining or epithelium of the firstand longest portion of the large intestine. Malignant cells have lostnormal control mechanisms governing growth. These cells may invadesurrounding local tissue, or they may spread throughout the body andinvade other organ systems. Colon cancer is thought to arisesporadically in about 80% of those who develop the disease. Twentypercent of people are thought to have genetic predisposition, meaningtheir genes carry a trigger for the disease. Development of colon cancerat an early age, or at multiple sites, or recurrent colon cancer,suggests a genetically transmitted form of the disease as opposed to thesporadic form.

Screening of colorectal cancer involves physical examination, simplelaboratory tests, and the visualization of the lining of the colon. Tovisualize the colon epithelium, clinicians use X rays (indirectvisualization) and endoscopy (direct visualization).

Proteins are sometimes produced by cancers, and these may be elevated inthe patient's blood. When this occurs, the protein produced is known asa tumor marker. There is a tumor marker for some cancers of the colon;it is known as carcinoembryonic antigen, or CEA. Unfortunately, thisprotein may be made by other adenocarcinomas as well, or it may not beproduced by a particular colon cancer. Therefore, screening by chemicalanalysis for CEA has not been helpful. CEA has been helpful when used ina follow-up role for patients treated for colon cancer if their tumormakes the protein.

The treatment of colorectal cancer depends on the staging of the cancer.Colon cancer is assigned stages I through IV based on the followinggeneral criteria: Stage I: the tumor is confined to the epithelium orhas not penetrated through the first layer of muscle in the bowel wall;Stage II: the tumor has penetrated through to the outer wall of thecolon or has gone through it, possibly invading other local tissue;Stage III: any depth or size of tumor associated with regional lymphnode involvement; Stage IV: any of previous criteria associated withdistant metastasis.

When colorectal cancer is caught at early stages (with little spread) itcan be curable. However when it is detected at later stages (whendistant metastases are present) it is less likely to be curable. Surgeryremains the primary treatment while chemotherapy and/or radiotherapy maybe recommended depending on the individual patient's staging and othermedical factors.

Surgery is used as primary therapy for stages I through III colon cancerunless there are signs that local invasion will not permit completeremoval of the tumor, as may occur in advanced stage III tumors.However, this circumstance is rare, occurring in less than 2% of allcolon cancer cases.

Surgical treatment of colon cancer usually involves removal of theinvolved segment of colon (colectomy) along with its blood supply andregional lymph nodes. Usually, the partial colectomies are separatedinto right, left, transverse, or sigmoid sections based on the bloodsupply. The removal of the blood supply at its origin along with theregional lymph nodes that accompany it ensures an adequate margin ofnormal colon on either side of the primary tumor. When the cancer liesin a position such that the blood supply and lymph drainage between twoof the major vessels, both vessels are taken to assure complete radicalresection or removal (extended radical right or left colectomy). If theprimary tumor penetrates through the bowel wall, any tissue adjacent tothe tumor extension is also taken if feasible.

Chemotherapy is useful for patients who have had all identifiable tumorremoved and are at risk for recurrence (adjuvant chemotherapy).Chemotherapy may also be used when the cancer is stage 1V and is beyondthe scope of regional therapy, but this use is rare.

Adjuvant therapy is considered in stage II disease with deep penetrationor in stage III patients. Standard therapy is treatment with5-fluorouracil, (5FU) combined with leucovorin for a period of six to 12months. 5FU is an antimetabolite, and leucovorin improves the responserate. (A response is a temporary regression of the cancer fromchemotherapy.) Another agent, levamisole, (which seems to stimulate theimmune system), may be substituted for leucovorin. These protocolsreduce rate of recurrence by about 15% and reduce mortality by about10%. The regimens do have some toxicity, but usually are toleratedfairly well.

Similar chemotherapy may be administered for stage 1V disease or if apatient progresses and develops metastases. Results show response ratesof about 20%. Unfortunately, these patients eventually succumb to thedisease, and this chemotherapy may not prolong survival or improvequality of life in Stage 1V patients. Clinical trials have now shownthat the results can be improved with the addition of another agent tothis regimen. Irinotecan does not seem to increase toxicity but itimproved response rates to 39%, added two to three months todisease-free survival, and prolonged overall survival by a little overtwo months.

Radiation therapy is used as an adjunct to surgery if there is concernabout potential for local recurrence post-operatively and the area ofconcern will tolerate the radiation. For instance, if the tumor invadedmuscle of the abdominal wall but was not completely removed, this areawould be considered for radiation. Radiation has significant dose limitswhen residual bowel is exposed to it because the small and largeintestine do not tolerate radiation well.

Radiation also is used in the treatment of patients with metastaticdisease. It is particularly useful in shrinking metastatic colon cancerto the brain.

Noncolorectal gastrointestinal cancers include pancreatic,hepatobiliary, gastric, small bowel, and esophageal cancer. Treatment ofnoncolorectal gastrointestinal cancers often includes a multimodalapproach combining surgery, radiotherapy, and chemotherapy.

Cancer of the stomach—also called gastric cancer or gastric carcinoma—isa treatable disease that can often be cured when it is found and treatedat a local stage. Stomach cancers are classified according to what sortof tissues they start in. The most common type arises in the glandulartissue lining the stomach. These tumors are called adenocarcinomas andaccount for over 95 percent of all stomach tumors. Metastases throughthe bloodstream can spread to the liver, lungs, bone and brain.Metastases are also found in the lining of the abdominal cavity(peritoneum) and around the rectum.

The ideal treatment of stomach cancer is radical surgery, meaning thatmost or all of the stomach is removed (subtotal or total gastrectomy),along with the surrounding lymph nodes. Radical surgery is the onlytreatment that can lead to a cure, though lesser surgical procedures canplay a significant role in therapy designed to relieve symptoms.Radiation and chemotherapy are also treatment options.

The immune system has the ability to recognize and destroy cells via twoseparate modalities: innate and adaptive immunity. The innate componentconsists of macrophages, natural killer (NK) cells, monocytes, andgranulocytes. These cells identify molecular patterns involved incellular transformation and release various cytokines and inflammatorymediators. The innate response lacks the memory capability for foreignantigens, a feature present in adaptive immune response.

This latter component of immune system also features specificity forforeign antigens, imparted by presence of receptors on lymphocytes.Antigen presenting cells (APCs) also play a role in the adaptiveresponse—they engulf foreign antigens and present them to thelymphocytes in the context of major histocompatibility complex. CD4+ Tcells bear receptors that recognize antigens in the context of MHC classII molecules, which then enables them to release cytokines and furtheractivate CD8+ lymphocytes (CTLs) or B cells. CTLs are part ofcell-mediated immunity and are capable of eliminating cells presented inthe context of MHC class I molecules, via apoptosis or perforin-mediatedcell lysis. It is widely accepted that T-cell mediated immunity plays avital role in the anti-tumor response.

B cells are involved in release of immunoglobulins and as such are partof the humoral immune system.

If properly aimed and enhanced, immune functions can be therapeuticallyexploited to control and even eradicate malignant lesions. Genetic andepigenetic changes involved in carcinogenesis generate antigens that arerecognized by the immune system in analogous fashion to microbialantigens.

Novel strategies for the treatment of colorectal cancer such as activeimmunization with dendritic cells (DCs), gene transfer of cytokines intotumor cells or administration of immunostimulatory monoclonal antibodieshave been assessed in preclinical studies and are at an early clinicaldevelopment stage. Importantly, there is accumulating evidence thatchemotherapy and immunotherapy can be combined in the treatment of somecases with colorectal cancer, with synergistic potentiation as a resultof antigens cross-presented by dendritic cells and/or elimination ofcompetitor or suppressive T lymphocyte populations (regulatory T-cells).

There is a need in the art for genetic markers and targets of colorectaltumors, in particular colon tumors, and gastric tumors and metastatictumors derived therefrom, allowing the design of specific, reliable andsensitive diagnostic and therapeutic approaches of these diseases.

The invention relates to the therapy and diagnosis of colorectal tumors,in particular colon tumors, and stomach tumors and metastatic tumorsderived therefrom. In particular, the invention relates to theidentification of molecular structures that are present on colorectaltumors and gastric tumors and can serve as targets for diagnostic andtherapeutic approaches of these diseases.

SUMMARY OF THE INVENTION

The present invention relates to the identification of nucleic acid andamino acid sequences that are characteristic of colorectal, inparticular colonic, and gastric tumor tissues and colorectal, inparticular colonic, and gastric tissues, and which represent targets fortherapy or diagnosis of such tumor diseases in a subject.

These sequences encompass proteins identified to be in the plasmamembrane of the cells, and accessible on the extra-cellular region, sothat the sequences may be useful in the preparation of tumor vaccines,including prophylatic and therapeutic vaccines.

The nucleic acids identified according to the invention to be expressedin tumor cells comprise the nucleic acid sequence according to SEQ IDNO: 1 of the sequence listing or a variant of said nucleic acidsequence. Preferably, the nucleic acids identified according to theinvention to be expressed in tumor cells encode a peptide comprising theamino acid sequence according to SEQ ID NO: 2 of the sequence listing ora variant of said amino acid sequence. These nucleic acids are alsotermed “tumor-associated nucleic acids” or simply “tumor nucleic acids”herein.

In another aspect, the invention relates to peptides encoded by thetumor nucleic acids identified according to the invention, also termed“tumor-associated antigens” or simply “tumor antigens” herein.Accordingly, the tumor antigens identified according to the inventioncomprise an amino acid sequence encoded by a nucleic acid whichcomprises the nucleic acid sequence according to SEQ ID NO: 1 of thesequence listing or a variant of said nucleic acid sequence. Preferably,the tumor antigens identified according to the invention comprise theamino acid sequence according to SEQ ID NO: 2 of the sequence listing ora variant of said amino acid sequence.

In one aspect, the invention provides peptides comprising amino acidsequences derived from the sequences of the tumor antigens identifiedaccording to the invention, also termed “tumor antigen peptides” herein.Preferably, the tumor antigen peptides of the invention are capable ofstimulating a cellular response against cells characterized bypresentation of a tumor antigen identified according to the inventionwith class I MHC and/or of elicting antibodies that specifically bind toa tumor antigen identified according to the invention when used itselfor attached to an immunogenic carrier. Preferred tumor antigen peptidesmay be presented, directly or following processing, with class I MHCmolecules. Preferably, the tumor antigen peptides according to theinvention are MHC class I and/or class II presented peptides or can beprocessed to produce MHC class I and/or class II presented peptides.Preferably, the tumor antigen peptides according to the inventioncomprise an amino acid sequence substantially corresponding to the aminoacid sequence of a fragment of a tumor antigen identified according tothe invention. Preferably, said fragment of a tumor antigen identifiedaccording to the invention is a MHC class I and/or class II presentedpeptide or is an immunogen that is capable of elicting antibodiesbinding to said fragment. Preferably, a tumor antigen peptide accordingto the invention comprises an amino acid sequence substantiallycorresponding to the amino acid sequence of such fragment and isprocessed to produce such fragment, i.e. a MHC class I and/or class IIpresented peptide derived from a tumor antigen identified according tothe invention or an immunogen derived from a tumor antigen identifiedaccording to the invention that is capable of elicting antibodiesbinding to said fragment. Thus, a tumor antigen peptide according to theinvention comprises an amino acid sequence substantially correspondingto the amino acid sequence of a fragment of a tumor antigen comprisingan amino acid sequence encoded by a nucleic acid which comprises thenucleic acid sequence according to SEQ ID NO: 1 of the sequence listingor a variant of said nucleic acid sequence and preferably comprises anamino acid sequence substantially corresponding to the amino acidsequence of a fragment of a tumor antigen comprising the amino acidsequence according to SEQ ID NO: 2 of the sequence listing or a variantof said amino acid sequence.

The present invention generally embraces the treatment and/or diagnosisof tumor diseases by targeting tumor nucleic acids or tumor antigens.These methods provide for the selective detection of cells and/oreradication of cells that express such tumor nucleic acids and/or tumorantigens thereby minimizing adverse effects to normal cells notexpressing such tumor nucleic acids and/or tumor antigens. Thus,preferred diseases for a therapy or diagnosis are those in which one ormore of the tumor nucleic acids and/or tumor antigens identifiedaccording to the invention are expressed such as tumor diseases, inparticular cancer diseases such as those described herein.

According to the invention, particularly suitable for targeting thetumor antigens identified according to the invention is a part of thetumor antigens which corresponds to the non-transmembrane portion, inparticular the extracellular portion of the tumor antigens or iscomprised thereof. Therefore, the entities used according to theinvention which are capable of binding to the tumor antigens identifiedaccording to the present invention preferably are capable of binding toa part of the tumor antigens identified according to the invention whichcorresponds to the non-transmembrane portion, in particular theextracellular portion of the tumor antigens or is comprised thereof.Similarly, peptides and nucleic acids used according to the inventionfor inducing an immune response with specificity to the tumor antigensidentified according to the present invention preferably inducespecificity for a part of the tumor antigens identified according to theinvention which corresponds to the non-transmembrane portion, inparticular the extracellular portion of the tumor antigens or iscomprised thereof. Preferably, said peptides comprise a sequencesubstantially corresponding to a part of the tumor antigens identifiedaccording to the invention which corresponds to the non-transmembraneportion, in particular the extracellular portion of the tumor antigensor is comprised thereof, and said nucleic acids encode such peptides.

One aspect of this invention relates to therapies for treatment of tumordiseases, in particular colorectal tumors such as colon tumors andgastric tumors, involving the administration of an inhibitor ofexpression and/or activity of a tumor antigen identified according tothe invention.

In this aspect, the present invention relates to a pharmaceuticalcomposition comprising an inhibitor of expression and/or activity of atumor antigen identified according to the invention. In one embodiment,said inhibitor is specific for a tumor nucleic acid identified accordingto the invention. In another embodiment, said inhibitor is specific fora tumor antigen identified according to the invention. According to theinvention the phrase “inhibit expression and/or activity” includes acomplete or essentially complete inhibition of expression and/oractivity and a reduction in expression and/or activity. Preferably, saidinhibition of expression of a tumor antigen identified according to theinvention may take place by inhibiting the production of or reducing thelevel of transcript, i.e. mRNA, coding for a tumor antigen identifiedaccording to the invention, e.g. by inhibiting transcription or inducingdegradation of transcript, and/or by inhibiting the production of tumorantigen identified according to the invention, e.g. by inhibitingtranslation of transcript coding for a tumor antigen identifiedaccording to the invention. Preferably, said inhibition of expressionand/or activity of a tumor antigen identified according to the presentinvention reduces tumor cell growth and/or induces tumor cell death andthus, has a tumor-inhibiting or tumor-destroying effect.

In a particular embodiment, the inhibitor of expression of a tumorantigen identified according to the invention is an inhibitory nucleicacid (e.g., anti-sense oligonucleotide, ribozyme, iRNA, siRNA or a DNAencoding the same) selectively hybridizing to and being specific for atumor nucleic acid identified according to the invention, therebyinhibiting (e.g., reducing) transcription and/or translation thereof.

Inhibitory nucleic acids of this invention include oligonucleotideshaving sequences in the antisense orientation relative to the targetnucleic acids. Suitable inhibitory oligonucleotides typically vary inlength from five to several hundred nucleotides, more typically about20-70 nucleotides in length or shorter, even more typically about 10-30nucleotides in length. These inhibitory oligonucleotides may beadministered as free (naked) nucleic acids or in protected forms, e.g.,encapsulated in liposomes. The use of liposomal or other protected formsmay be advantageous as it may enhance in vivo stability and thusfacilitate delivery to target sites.

Also, the target tumor nucleic acid may be used to design ribozymes thattarget the cleavage of the corresponding mRNAs in tumor cells.Similarly, these ribozymes may be administered in free (naked) form orby the use of delivery systems that enhance stability and/or targeting,e.g., liposomes.

Also, the target tumor nucleic acid may be used to design siRNAs thatcan inhibit (e.g., reduce) expression of the tumor nucleic acid. ThesiRNAs may be administered in free (naked) form or by the use ofdelivery systems that enhance stability and/or targeting, e.g.,liposomes. They may also be administered in the form of their precursorsor encoding DNAs.

siRNA preferably comprises a sense RNA strand and an antisense RNAstrand, wherein the sense and antisense RNA strands form an RNA duplex,and wherein the sense RNA strand comprises a nucleotide sequencesubstantially identical to a target sequence of about 19 to about 25contiguous nucleotides in a tumor nucleic acid identified according tothe invention, preferably mRNA coding for the target tumor antigen.

In a further embodiment, the inhibitor of activity of a tumor antigenidentified according to the invention is an antibody that specificallybinds to said tumor antigen. Binding of the antibody to the tumorantigen can interfere with the function of the tumor antigen, e.g. byinhibiting binding activity or catalytic activity.

Also, the present invention in another aspect relates to therapies fortreatment of tumor diseases involving the administration of a ligand ofa target molecule, i.e. a tumor nucleic acid or tumor antigen identifiedaccording to the invention. In this respect, a nucleic acid may beadministered that selectively hybridizes to the target nucleic acid oran antibody may be administered that specifically binds to a targetantigen, attached to therapeutic effector moieties, e.g., radiolabels,cytotoxins, cytotoxic enzymes, and the like in order to selectivelytarget and kill cells that express these targets, e.g. tumor cells.

In this aspect, the present invention relates to a pharmaceuticalcomposition, comprising a ligand of a tumor nucleic acid or tumorantigen identified according to the invention, said ligand beingattached to one or more therapeutic effector moieties. Preferably, saidligand is specific for said tumor nucleic acid or tumor antigen. In oneembodiment, said ligand of a tumor nucleic acid or tumor antigen reducestumor cell growth and/or induces tumor cell death and thus, has atumor-inhibiting or tumor-destroying effect.

According to a further aspect of the invention, the identification oftumor nucleic acids and tumor antigens makes it possible to developspecific immunotherapies based on attacking tumor cells bearing theidentified antigens, thereby delaying or preventing the development of atumor disease or eradicating tumor cells. Immunotherapy encompasses avariety of interventions and techniques with the common goal ofeliciting tumor cell destructive immune responses. A variety of clinicalapproaches utilising these nucleic acids and antigens are possible assummarised below. Approaches to cancer immunotherapy can be divided intoactive and passive categories. Active immunotherapy may involve thedirect immunization of patients with antigens or nucleic acids encodingsuch antigens in an attempt to boost immune responses against the tumor.Passive immunotherapy refers to the administration of immune reagentswith the goal of directly mediating antitumor responses. The presentinvention contemplates both approaches.

In this aspect, the invention relates to a pharmaceutical compositionwhich comprises one or more agents selected from the group consisting of(i) a peptide comprising the amino acid sequence of a tumor antigenidentified according to the invention or of a tumor antigen peptidederived from said tumor antigen, or a derivative of said peptide, (ii) anucleic acid which codes for a peptide comprising the amino acidsequence of a tumor antigen identified according to the invention or ofa tumor antigen peptide derived from said tumor antigen, or a derivativeof said nucleic acid, (iii) a host cell which codes for a peptidecomprising the amino acid sequence of a tumor antigen identifiedaccording to the invention or of a tumor antigen peptide derived fromsaid tumor antigen, (iv) a virus which codes for a peptide comprisingthe amino acid sequence of a tumor antigen identified according to theinvention or of a tumor antigen peptide derived from said tumor antigen,(v) a cell presenting a peptide comprising the amino acid sequence of atumor antigen peptide derived from a tumor antigen identified accordingto the invention, or a derivative of said peptide, (vi) an antibody or Tcell receptor which binds to a peptide comprising the amino acidsequence of a tumor antigen identified according to the invention or ofa tumor antigen peptide derived from said tumor antigen, (vii) animmunoreactive cell sensitized in vitro to recognize a peptidecomprising the amino acid sequence of a tumor antigen identifiedaccording to the invention or of a tumor antigen peptide derived fromsaid tumor antigen, and (viii) an effector cell (or stem cell)transduced with a nucleic acid encoding a T cell receptor thatrecognises a peptide comprising the amino acid sequence of a tumorantigen identified according to the invention or of a tumor antigenpeptide derived from said tumor antigen.

In one embodiment, a peptide according to (i) is a tumor antigenspecific MHC class I or class II presented peptide or can be processedto produce a tumor antigen specific MHC class I or class II presentedpeptide, preferably a tumor antigen specific MHC class I presentedpeptide. Preferably, said peptide has a sequence substantiallycorresponding to a fragment of a tumor antigen identified according tothe invention which is presented by MHC class I or class II, preferablyMHC class I or can be processed to produce a peptide fragment havingsuch sequence. Preferably, said peptide is capable of stimulating acellular response against a tumor characterized by presentation of atumor antigen identified according to the invention with class I MHCand/or is capable of stimulating a humoral immune response against atumor characterized by expression of a tumor antigen identifiedaccording to the invention.

In one embodiment, a nucleic acid according to (ii) codes for a tumorantigen specific MHC class I or class II presented peptide or codes fora peptide which can be processed to produce a tumor antigen specific MHCclass I or class II presented peptide, preferably a tumor antigenspecific MHC class I presented peptide.

Preferably, said peptide has a sequence substantially corresponding to afragment of a tumor antigen identified according to the invention whichis presented by MHC class I or class II, preferably MHC class I or canbe processed to produce a peptide fragment having such sequence.Preferably, said peptide is capable of stimulating a cellular responseagainst a tumor characterized by presentation of a tumor antigenidentified according to the invention with class I MHC and/or is capableof stimulating a humoral immune response against a tumor characterizedby expression of a tumor antigen identified according to the invention.Such nucleic acid may be present in a plasmid or an expression vectorand may be functionally linked to a promoter.

In one embodiment, a host cell according to (iii) codes for a tumorantigen specific MHC class I or class II presented peptide or codes fora peptide which can be processed to produce a tumor antigen specific MHCclass I or class II presented peptide, preferably a tumor antigenspecific MHC class I presented peptide. Preferably, said peptide has asequence substantially corresponding to a fragment of a tumor antigenidentified according to the invention which is presented by MHC class Ior class II, preferably MHC class I or can be processed to produce apeptide fragment having such sequence. Preferably, said peptide iscapable of stimulating a cellular response against a tumor characterizedby presentation of a tumor antigen identified according to the inventionwith class I MHC and/or is capable of stimulating a humoral immuneresponse against a tumor characterized by expression of a tumor antigenidentified according to the invention. The host cell may be arecombinant cell and may secrete the encoded peptide or a processionproduct thereof, may express it on the surface and preferably mayadditionally express an MHC molecule which binds to said peptide or aprocession product thereof and preferably presents said peptide or aprocession product thereof on the cell surface. In one embodiment, thehost cell expresses the MHC molecule endogenously. In a furtherembodiment, the host cell expresses the MHC molecule and/or the peptideor the procession product thereof in a recombinant manner. The host cellis preferably nonproliferative. In a preferred embodiment, the host cellis an antigen-presenting cell, in particular a dendritic cell, amonocyte or a macrophage.

In one embodiment, a virus according to (iv) codes for a tumor antigenspecific MHC class I or class II presented peptide or codes for apeptide which can be processed to produce a tumor antigen specific MHCclass I or class II presented peptide, preferably a tumor antigenspecific MHC class I presented peptide. Preferably, said peptide has asequence substantially corresponding to a fragment of a tumor antigenidentified according to the invention which is presented by MHC class Ior class II, preferably MHC class I or can be processed to produce apeptide fragment having such sequence. Preferably, said peptide iscapable of stimulating a cellular response against a tumor characterizedby presentation of a tumor antigen identified according to the inventionwith class I MHC and/or is capable of stimulating a humoral immuneresponse against a tumor characterized by expression of a tumor antigenidentified according to the invention.

In one embodiment, a cell according to (v) endogenously expresses an MHCmolecule. In a further embodiment, the cell recombinantly expresses anMHC molecule and/or a peptide comprising the amino acid sequence of atumor antigen peptide derived from a tumor antigen identified accordingto the invention. Preferably, the cell presents the peptide comprisingthe amino acid sequence of a tumor antigen peptide derived from a tumorantigen identified according to the invention, or a derivative of saidpeptide by MHC molecules on its surface. Preferably, the presentedpeptide is a peptide having a sequence substantially corresponding to afragment of a tumor antigen identified according to the invention whichis presented by MHC class I or class II, preferably MHC class I. Thecell is preferably nonproliferative. In a preferred embodiment, the cellis an antigen-presenting cell such as a dendritic cell, a monocyte or amacrophage. Thus, in a preferred embodiment, the cell according to (v)is an antigen presenting cell that comprises a tumor antigen peptide asdescribed herein presented with class I MHC.

In one embodiment, an antibody according to (vi) is a monoclonalantibody. In further embodiments, the antibody is a chimeric, human orhumanized antibody, or is a fragment of an antibody or a syntheticantibody. The antibody may be coupled to a therapeutic effector moietyor a detectable label. Preferably, the antibody or T cell receptoraccording to (vi) binds to a sequence in the peptide substantiallycorresponding to a fragment of a tumor antigen identified according tothe invention.

Preferably, a cell according to (vii) binds to a sequence in the peptidesubstantially corresponding to a fragment of a tumor antigen identifiedaccording to the invention which fragment is preferably presented by MHCclass I or class II, preferably MHC class I. In one embodiment, a cellaccording to (vii) is obtainable by a method comprising the steps of (a)providing a sample containing immunoreactive cells, either obtained froma patient or from another individual of the same species, in particulara healthy individual, or an individual of a different species, (b)contacting said sample with cells presenting a peptide comprising anamino acid sequence substantially corresponding to a fragment of a tumorantigen identified according to the invention, or a derivative of saidpeptide, under conditions which favor production of CTLs against saidpeptide, and (c) introducing the CTLs into the patient in an amountsuitable for lysing cells expressing the tumor antigen and preferablypresenting it with class I MHC such as tumor cells.

In one embodiment, the method includes cloning of the T cell receptor ofCTLs obtained and transferring the nucleic acid coding for the T cellreceptor to effector cells such as CTLs or immature CTLs, eitherobtained from said patient or from another individual of the samespecies, in particular a healthy individual, or an individual of adifferent species, which effector cells thus receive the desiredspecificity and may be introduced into the patient. Effector cellsaccording to (viii) can be produced in this way.

Vaccination using agents as described above may provide MHC classII-presented epitopes that are capable of eliciting a CD4+ helper T-cellresponse and/or a CD8+ T-cell response against tumor antigens identifiedaccording to the invention, in particular if expressed in cells such astumor cells. Alternatively or additionally, vaccination using agents asdescribed above may provide MHC class I-presented epitopes that arecapable of eliciting a CD8+ T-cell response against tumor antigensidentified according to the invention, in particular if expressed incells such as tumor cells. Furthermore, vaccination using agents asdescribed above may elicit antibodies specific for a tumor antigenidentified according to the invention.

In one embodiment, the pharmaceutical composition of the presentinvention is a therapeutic or prophylactic anti-tumor vaccine preferablyfurther comprising an immunomodulatory agent, or a nucleic acid encodingthe same. In one embodiment, the immunomodulatory agent is an agonist ofa positive costimulatory molecule, e.g., an Ig-fusion protein capable ofeffecting costimulation of a CTL. In another embodiment, thecostimulatory agent is an antagonist of a negative costimulatorymolecule, e.g., an antibody capable of reducing inhibition of CTLcostimulation. In a preferred embodiment, the immunomodulatory agent isan anti-CTLA4 antibody.

A pharmaceutical composition of the invention may comprise apharmaceutically acceptable carrier and may optionally comprise one ormore adjuvants, stabilizers etc.

Another aspect of the invention involves the use of the agents andcompositions described herein for a prophylactic and/or therapeutictreatment of tumor diseases.

In one aspect, the invention provides therapeutic and prophylacticmethods of treating a patient having a tumor disease or being at risk ofdeveloping a tumor disease. In one aspect, the invention providesmethods for inhibiting tumor growth. In one aspect, the inventionprovides methods for inducing tumor cell death.

Preferably, the tumor disease is a cancer disease, preferably selectedfrom the group consisting of colorectal cancer, in particular coloncancer, gastric cancer, metastatic colorectal cancer, in particularcolon cancer, and metastatic gastric cancer. In one embodiment, thetumor cell is a cell of such a cancer.

According to various embodiments, the methods of the invention comprisethe administration of an inhibitor of expression and/or activity of atumor antigen identified according to the invention, of a ligand of atumor nucleic acid or of a tumor antigen identified according to theinvention and/or of one or more immunotherapeutic agents as describedherein. In one embodiment, the methods involve administering apharmaceutical composition as described herein to a patient andpreferably vaccinating a patient with an anti-tumor vaccine describedherein. Any of the wide variety of vaccination methods known in the artmay be used according to the present invention. Anti-tumor vaccines ofthe invention are preferably capable of inducing or promoting CTLactivity against a tumor characterized by presentation of a tumorantigen identified according to the invention with class I MHC. Thesemay be used in combination with adjuvants, which facilitate stimulationof the immune system by acting on T cells directly or through APCs.Adjuvants include immunomodulatory substances having a positiveimmunomodulatory effect, as described herein.

In various embodiment, the methods of the invention involve thestimulation of an anti-tumor CTL response against tumor cells expressinga tumor antigen identified according to the invention and preferablypresenting a tumor antigen identified according to the invention withclass I MHC, the inhibition of the growth of tumor cells expressing atumor antigen identified according to the invention and preferablypresenting a tumor antigen identified according to the invention withclass I MHC, and/or the induction of the death of cells expressing atumor antigen identified according to the invention and preferablypresenting a tumor antigen identified according to the invention withclass I MHC.

In one aspect, the invention provides an inhibitor of expression and/oractivity of a tumor antigen identified according to the invention, aligand of a tumor nucleic acid or of a tumor antigen identifiedaccording to the invention and/or one or more immunotherapeutic agentsas described herein for use in the methods of treatment describedherein. In one embodiment, the invention provides a pharmaceuticalcomposition as described herein for use in the methods of treatmentdescribed herein.

The treatments based on targeting tumor nucleic acids or tumor antigenssuch as the immunotherapies described herein can be combined withsurgical resection and/or radiation and/or traditional chemotherapy.

Another object of the invention is to provide methods for diagnosis,detection or monitoring, i.e. determining the regression, progression,course and/or onset, of a tumor disease. Preferably said methods involvethe use of ligands such as monoclonal antibodies and nucleic acid probeswhich specifically bind to a target molecule. Suitable target moleculesare (i) a tumor nucleic acid identified according to the invention, (ii)a tumor antigen identified according to the invention or a tumor antigenpeptide derived therefrom, (iii) an antibody against a tumor antigenidentified according to the invention or a tumor antigen peptide derivedtherefrom, (iv) a T cell which recognizes a tumor antigen identifiedaccording to the invention or a tumor antigen peptide derived therefromand/or (v) a cell which presents a tumor antigen peptide derived from atumor antigen identified according to the invention with class I orclass II MHC, preferably class I MHC. Such methods may be used to detectwhether a subject has or is at (increased) risk of developing a tumordisease, or, for instance, whether a treatment regimen is efficient.

Accordingly, the present invention relates to methods for diagnosis,detection or monitoring of a tumor disease comprising the detection ofand/or determination of the quantity of one or more parameters selectedfrom the group consisting of (i) a nucleic acid which comprising thenucleic acid sequence of a tumor nucleic acid identified according tothe invention/a nucleic acid which codes for a peptide comprising theamino acid sequence of a tumor antigen identified according to theinvention, (ii) a peptide comprising the amino acid sequence of a tumorantigen identified according to the invention or of a tumor antigenpeptide derived from said tumor antigen, (iii) an antibody which bindsto a peptide comprising the amino acid sequence of a tumor antigenidentified according to the invention or of a tumor antigen peptidederived from said tumor antigen, (iv) a T cell that recognises a peptidecomprising the amino acid sequence of a tumor antigen identifiedaccording to the invention or of a tumor antigen peptide derived fromsaid tumor antigen and/or (v) a cell which presents a peptide comprisingthe amino acid sequence of a tumor antigen peptide derived from a tumorantigen identified according to the invention with class I or class IIMHC, preferably class I MHC, in a biological sample isolated from apatient, preferably from a patient having a tumor disease, beingsuspected of having or falling ill with a tumor disease or having apotential for a tumor disease.

In one embodiment, a nucleic acid according to (i) codes for a peptidewhich is processed to produce a tumor antigen specific MHC class I orclass II presented peptide, preferably, a tumor antigen specific MHCclass I presented peptide.

In one embodiment, a peptide according to (ii) is a tumor antigenspecific MHC class I or class II presented peptide or can be processedto produce a tumor antigen specific MHC class I or class II presentedpeptide, preferably, a tumor antigen specific MHC class I presentedpeptide.

Preferably, a T cell according to (iv) recognizes a sequence in thepeptide substantially corresponding to a fragment of a tumor antigenidentified according to the invention which is presented by MHC class Ior class II, preferably MHC class I.

In one embodiment, a cell according to (v) presents the peptide by MHCclass I or class II, preferably MHC class I on its surface. The cell ispreferably nonproliferative. In a preferred embodiment, the cell is anantigen-presenting cell such as a dendritic cell, a monocyte or amacrophage. Thus, in a preferred embodiment, the cell according to (v)is an antigen presenting cell that comprises a tumor antigen peptide asdescribed herein presented with class I MHC. In another embodiment, thecell is a tumor cell.

In one embodiment, the nucleic acid according to (i) or the peptideaccording to (ii) is detected or its quantity determined in situ in acell, preferably a tumor cell. In one embodiment, the peptide accordingto (ii) is detected or its quantity determined in situ on the surface ofa cell, either incorporated in the plasma membrane or in a complex withMHC class I or class II, preferably MHC class I.

In one embodiment of the methods for diagnosis, detection or monitoringof a tumor disease the biological sample is from a tissue or organwherein the cells when the tissue or organ is free of tumors do notsubstantially express a tumor antigen identified according to theinvention and/or a tumor nucleic acid identified according to theinvention. Preferably said tissue is a tissue other than colon tissue orgastric tissue. Preferably, said tissue is tissue of small intestine,brain, breast, liver, lung, pancreas, kidney, prostate, spleen, lymphnode, endometrium, esophagus, placenta, ovary, testis, uterus, skin,thymus, bladder, muscle and cervix.

According to the invention a tumor antigen and/or a tumor nucleic acidis not substantially expressed if the level of expression is lowercompared to expression in colon cells and/or stomach cells or colontissue and/or stomach tissue. Preferably, the level of expression isless than 10%, preferably less than 5%, 3%, 2%, 1%, 0.5%, 0.1% or 0.05%or even lower compared to colon cells and/or stomach cells or colontissue and/or stomach tissue. Preferably, a tumor antigen and/or anucleic acid is not substantially expressed if the level of expressionis below the detection limit.

The methods for diagnosis, detection or monitoring allow quantitativeand/or qualitative evaluations, e.g., absolute and/or relative measureof target molecules e.g. expression levels of a tumor nucleic acid or atumor antigen.

Means for accomplishing said detection and/or determination of thequantity are described herein and will be apparent to the skilledperson.

Preferably, the detection and/or determination of the quantity in themethods of the invention comprises (i) contacting a biological samplewith an agent which binds specifically to the nucleic acid, the peptide,the antibody, the T cell or the cell which is to be detected and/or theamount of which is to be determined, and (ii) detecting the formation ofand/or determining the quantity of a complex between the agent and thenucleic acid, the peptide, the antibody, the T cell or the cell which isto be detected or the amount of which is to be determined.

Typically, the level of a target molecule in a biological sample iscompared to a reference level, wherein a deviation from said referencelevel is indicative of the presence and/or stage of a tumor disease in asubject. The reference level may be a level as determined in a controlsample (e.g., from a healthy tissue or subject) or a median level fromhealthy subjects. A “deviation” from said reference level designates anysignificant change, such as an increase or decrease by at least 10%,20%, or 30%, preferably by at least 40% or 50%, or even more.Preferably, the presence of the nucleic acid, the peptide, the antibody,the T cell and/or the cell in said biological sample or a quantity ofthe nucleic acid, the peptide, the antibody, the T cell and/or the cellin the biological sample which is increased compared to a referencelevel indicates the presence of a tumor disease.

Typically, the detection and/or determination of the quantity in themethods of the invention involves the use of labeled ligands whichspecifically bind to a target molecule, e.g. a labeled nucleic acidprobe that hybridizes to a target nucleic acid and/or a labeled antibodyor fragment/derivative thereof that specifically binds to a targetpeptide.

According to the invention, detection of a nucleic acid or determiningthe quantity of a nucleic acid may be carried out using known nucleicacid detection methods such as methods involving hybridization ornucleic acid amplification techniques. In one embodiment, mRNAtranscripts are detected or the quantity thereof is determined usingRT-PCR or Northern blot analysis.

Such nucleic acid detection methods may involve the use ofoligonucleotides hybridizing to the target nucleic acids. Suitableoligonucleotides typically vary in length from five to several hundrednucleotides, more typically about 20-70 nucleotides in length orshorter, even more typically about 10-30 nucleotides in length.

According to the invention, detection of a peptide or determining thequantity of a peptide may be carried out in a number of ways, includingbut not limited to immunodetection using an antibody bindingspecifically to said peptide. Preferably, the antibody binds to asequence substantially corresponding to a fragment of a tumor antigenidentified according to the invention.

Methods for using antibodies to detect peptides are well known andinclude ELISA, competitive binding assays, and the like. In general,such assays use an antibody or antibody fragment that specifically bindsthe target peptide directly or indirectly bound to a label that providesfor detection, e.g. indicator enzymes, radiolabels, fluorophores, orparamagnetic particles.

According to the invention, detection of an antibody or determining thequantity of an antibody may be carried out using a peptide bindingspecifically to said antibody.

T cells may be isolated from patient peripheral blood, lymph nodes,tissue samples such as derived from biopsy and resection, or othersource. Reactivity assays may be performed on primary T cells or otherappropriate derivatives. For example, T cells may be fused to generatehybridomas. Assays for measuring T cell responsiveness are known in theart, and include proliferation assays and cytokine release assays.

In one embodiment, the T cell that recognises a peptide comprising theamino acid sequence of a tumor antigen identified according to theinvention or of a tumor antigen peptide derived from said tumor antigenis a tumor antigen-responsive CTL.

A CTL may be detected and its quantity determined in a number of ways,including but not limited to the following preferred embodiments. In oneembodiment, CTLs are directly stained using an appropriate fluorescenttumor antigen peptide/MHC tetramer. In another embodiment, the “TRAP”assay (“T-cell recognition of APCs by protein transfer”) is used (see,for example, Beadling et al. Nature Medicine 12:1208 (2006)). In anotherembodiment, detection of T cells in blood samples is performed usingmethods outlined by Yuan et al. (Cytotherapy 8:498, 2006). Assays andindices for detecting reactive T cells are known, and include but arenot limited to the use of IFN-gamma ELISPOT and IFN-gamma intracellularcytokine staining.

Other various methods are known in the art for determining whether a Tcell clone will respond to a particular antigenic peptide. Typically thepeptide is added to a suspension of the T cells for a period of from oneto three days. The response of the T cells may be measured byproliferation, e.g., uptake of labeled thymidine, or by release ofcytokines, e.g., IL-2. Various assays are available for detecting thepresence of released cytokines.

T cell cytotoxic assays can be used to detect cytotoxic T cells havingspecificity for tumor antigens. In one embodiment, cytotoxic T cells aretested for their ability to kill target cells presenting tumor antigenpeptide with MHC class I molecules. Target cells presenting tumorantigen peptide may be labeled and added to a suspension of T cells froma patient sample. The cytotoxicity may be measured by quantitating therelease of label from lysed cells. Controls for spontaneous and totalrelease may be included in the assay.

A cell presenting a peptide may be detected and its quantity determinedby testing for its ability to induce a cellular response, e.g. toactivate T cells, or measuring lysis of cells by CTLs having specificityfor such cell.

The presence of said nucleic acid, said peptide, said antibody, said Tcell and/or said cell which is to be detected and/or the quantity ofwhich is to be determined and/or a quantity of said nucleic acid, saidpeptide, said antibody, said T cell and/or said cell which is increasedcompared to a reference level, e.g. compared to a patient without atumor disease, may indicate the presence of or risk for (i.e. apotential for a development of) a tumor disease in said patient. In oneembodiment, the presence of said nucleic acid, said peptide, saidantibody, said T cell and/or said cell which is to be detected and/orthe quantity of which is to be determined and/or a quantity of saidnucleic acid, said peptide, said antibody, said T cell and/or said cellwhich is increased compared to a reference level, e.g. compared to apatient without a tumor disease, may indicate the presence of or riskfor metastatic colorectal cancer, in particular metastatic colon cancer,or metastatic gastric cancer in said patient.

In one embodiment, the biological sample is from a tissue or organwherein the cells when the tissue or organ is free of tumors do notsubstantially express a tumor antigen identified according to theinvention and/or a tumor nucleic acid identified according to theinvention. The indication of the presence of or risk for a tumor diseasein a patient by the methods of the invention may indicate that the tumordisease is in said tissue or organ or that said tissue or organ is atrisk for said tumor disease.

In one embodiment, the biological sample is from a tissue or organwherein the cells when the tissue or organ is free of tumors do notsubstantially express a tumor antigen identified according to theinvention and/or a tumor nucleic acid identified according to theinvention and the tissue or organ has already been diagnosed as beingaffected by a tumor disease, e.g. by visual inspection or culturetesting of cells of said tissue or organ. In this embodiment, thepresence of said nucleic acid, said peptide, said antibody, said T celland/or said cell which is to be detected and/or the quantity of which isto be determined and/or a quantity of said nucleic acid, said peptide,said antibody, said T cell and/or said cell which is increased comparedto a reference level, e.g. compared to a patient without a tumordisease, may indicate that the tumor disease is metastatic colorectalcancer, in particular metastatic colon cancer, or metastatic gastriccancer.

The indication of the presence of or risk for metastatic colorectalcancer, in particular metastatic colon cancer, or metastatic gastriccancer in a patient by the methods of the invention may also indicatethe presence of or risk for colorectal cancer, in particular coloncancer, and gastric cancer in said patient.

The methods for diagnosis, detection or monitoring of a tumor disease ofthe invention also include embodiments wherein by detection ordetermination of the quantity of said nucleic acid, said peptide, saidantibody, said T cell and/or said cell it is possible to assess and/orprognose the metastatic behavior of a tumor disease, wherein,preferably, the presence of said nucleic acid, said peptide, saidantibody, said T cell and/or said cell and/or a quantity of said nucleicacid, said peptide, said antibody, said T cell and/or said cell which isincreased compared to a reference level, e.g. a patient without saiddisease or without a metastasis of said disease, may indicate ametastatic behavior of a tumor disease or a risk for a metastaticbehavior of a tumor disease.

In one embodiment, the biological sample is from a tissue or organwherein the cells when the tissue or organ is free of tumors do notsubstantially express a tumor antigen identified according to theinvention and/or a tumor nucleic acid identified according to theinvention. In one embodiment, the tumor disease is in said tissue ororgan.

The methods of monitoring according to the invention preferably comprisea detection of and/or determination of the quantity of one or more ofthe parameters mentioned above in a first sample at a first point intime and in a further sample at a second point in time, wherein theregression, progression, course and/or onset of a tumor disease may bedetermined by comparing the two samples.

A quantity of said nucleic acid, said peptide, said antibody, said Tcell and/or said cell which is decreased in a biological sample comparedto a biological sample taken earlier from a patient may indicate aregression, a positive course, e.g. a successful treatment, or a reducedrisk for an onset of a tumor disease, e.g. metastatic colorectal cancer,in particular metastatic colon cancer, or metastatic gastric cancer, insaid patient.

In one embodiment, the biological sample is from a tissue or organwherein the cells when the tissue or organ is free of tumors do notsubstantially express a tumor antigen identified according to theinvention and/or a tumor nucleic acid identified according to theinvention. In one embodiment, the tumor disease is in said tissue ororgan.

A quantity of said nucleic acid, said peptide, said antibody, said Tcell and/or said cell which is increased in a biological sample comparedto a biological sample taken earlier from a patient may indicate aprogression, a negative course, e.g. an unsuccessful treatment,recurrence or metastatic behaviour, an onset or a risk for an onset of atumor disease, e.g. metastatic colorectal cancer, in particularmetastatic colon cancer, or metastatic gastric cancer, in said patient.

In one embodiment, the biological sample is from a tissue or organwherein the cells when the tissue or organ is free of tumors do notsubstantially express a tumor antigen identified according to theinvention and/or a tumor nucleic acid identified according to theinvention. In one embodiment, the tumor disease is in said tissue ororgan.

In a particular aspect, the invention relates to a method for detection,i.e. determining the position or site, of a tumor disease, e.g. aparticular tissue or organ. In one embodiment said method comprisesadministering an antibody which binds to a tumor antigen identifiedaccording to the present invention and which is coupled to a detectablelabel to a patient. The antibody may be a monoclonal antibody. Infurther embodiments, the antibody is a chimeric, human or humanizedantibody, a fragment of an antibody or a synthetic antibody.

Labelling of a tissue or organ in said patient may indicate the presenceof or risk for a tumor disease, e.g. metastatic colorectal cancer, inparticular metastatic colon cancer, or metastatic gastric cancer, insaid tissue or organ.

In one embodiment, the tissue or organ is a tissue or organ wherein thecells when the tissue or organ is free of tumors do not substantiallyexpress a tumor antigen identified according to the invention and/or atumor nucleic acid identified according to the invention.

In one embodiment, the tissue or organ is a tissue or organ wherein thecells when the tissue or organ is free of tumors do not substantiallyexpress a tumor antigen identified according to the invention and/or atumor nucleic acid identified according to the invention and the tissueor organ has already been diagnosed as being affected by a tumordisease, e.g. by visual inspection or culture testing of cells of saidtissue or organ. In this embodiment, the labelling of the tissue ororgan may indicate that the tumor disease is metastatic colorectalcancer, in particular metastatic colon cancer, or metastatic gastriccancer.

The indication of the presence of or risk for metastatic colorectalcancer, in particular metastatic colon cancer, or metastatic gastriccancer in a tissue or organ by the methods of the invention may alsoindicate the presence of or risk for colorectal cancer, in particularcolon cancer, and gastric cancer in the patient.

Preferably the tumor disease in the methods for diagnosis, detection ormonitoring of a tumor disease of the invention is a tumor disease of atissue other than colon tissue or gastric tissue. Preferably, saidtissue is tissue of small intestine tissue, brain, breast, liver, lung,pancreas, kidney, prostate, spleen, lymph node, endometrium, esophagus,placenta, ovary, testis, uterus, skin, thymus, bladder, muscle andcervix. In a further aspect, the tumor disease is selected from thegroup consisting of metastatic colon cancer and metastatic gastriccancer.

A positive diagnosis of a tumor disease and/or a metastatic tumordisease and/or a recurrence of a tumor disease as described above usingthe methods of the present invention may indicate a tumor disease and/ora metastatic tumor disease and/or a recurrence of a tumor disease whichis amenable to the methods of treatment described herein.

Circulating tumor cells (CTCs) have been observed in the peripheralblood of patients with epithelial-derived cancers at ultra lowconcentrations. The number of these cells has been shown to correlatewith outcome for cohorts of metastatic cancer patients with progressivedisease at the time of sampling. Some reports suggest a prognostic rolefor circulating tumor cells in patients affected by colon cancer.Consequently, an instrument for measuring circulating tumor cells, couldbe a valuable diagnostic tool.

The present invention satisfies this need by providing an epithelialcell specific marker, i.e. the tumor nucleic acids and tumor antigensidentified according to the present invention. This epithelial cellspecific marker is useful in methods for detecting circulating tumorcells in a patient. The methods may indicate the presence of metastaticcancer or an early stage cancer. In one aspect of the method, thepresence of circulating tumor cells in the specimen indicates thelikelihood of cancer recurrence in the mammalian subject. In a furtheraspect of the method, the presence of the circulating tumor cells in thespecimen indicates the cancer remission status in the mammalian subject.

Accordingly, the present invention relates to a method for detectingcirculating tumor cells in a patient comprising the detection of and/ordetermination of the quantity of (i) a nucleic acid which comprises thenucleic acid sequence of a tumor nucleic acid identified according tothe invention/a nucleic acid which codes for a peptide comprising theamino acid sequence of a tumor antigen identified according to theinvention and/or (ii) a peptide comprising the amino acid sequence of atumor antigen identified according to the invention or of a tumorantigen peptide derived from said tumor antigen in a biological samplecontaining or suspected of containing disseminating or circulating tumorcells or metastatic tumor cells isolated from said patient. Preferablythe patient is a patient having a tumor disease, being suspected ofhaving or falling ill with a tumor disease or having a potential for atumor disease.

Thus, in the methods for detecting circulating tumor cells of theinvention tumor nucleic acids identified according to the inventionand/or tumor antigens identified according to the invention or tumorantigen peptides derived therefrom are used as target molecules toidentify cells which are characterized by the presence of said targetmolecules. These cells are likely to represent circulating tumor cells.

In one embodiment, the nucleic acid or the peptide is detected or itsquantity determined in situ in a cell, preferably a tumor cell. In oneembodiment, the peptide is detected or its quantity determined in situon the surface of a cell, either incorporated in the plasma membrane orin a complex with MHC class I or class II, preferably MHC class I. Meansfor accomplishing said detection and/or determination of the quantity ofsuch target molecules are described herein and will be apparent to theskilled person.

A biological sample containing or suspected of containing disseminatingor circulating tumor cells or metastatic tumor cells includes, forexample, blood, serum, bone marrow, sputum, bronchial aspirate, and/orbronchial lavage.

In one aspect of the method, the presence of said nucleic acid accordingto (i) and/or said peptide according to (ii) in said biological sampleor a quantity of said nucleic acid and/or said peptide in saidbiological sample which is increased compared to a reference levelindicates the presence of circulating tumor cells in said patient.

In one aspect of the method, the presence of circulating tumor cells inthe sample may indicate the presence of or risk for a tumor disease, inparticular a metastatic tumor disease in the patient. In a furtheraspect, the presence of circulating tumor cells in the sample mayindicate the presence of or risk for an early stage tumor disease in thepatient. In a further aspect, the presence of circulating tumor cells insaid patient may indicate the presence of or risk for a tumor diseaseselected from the group consisting of colorectal cancer, in particularcolon cancer, gastric cancer, metastatic colorectal cancer, inparticular metastatic colon cancer, and metastatic gastric cancer.

In particular embodiments, the methods of the invention make possible toassess and/or prognose the success of a cancer therapy which has beenadministered or will be administered. In one aspect of the method, thepresence of the circulating tumor cells in the sample may indicate thepresence of or risk for tumor metastasis or tumor recurrence in thepatient. In a further aspect of the method, the presence of thecirculating tumor cells in the sample may indicate the tumor remissionstatus in the patient.

The detection of circulating tumor cells using the methods for detectingcirculating tumor cells of the invention may indicate a tumor diseaseand/or a metastasis of a tumor disease and/or a relapse of a tumordisease which is amenable to the methods of treatment described herein.

In a detailed aspect, the presence of the circulating tumor cells in thesample may indicate the presence of or risk for cancer including, butnot limited to, lymphoma, myeloma, neuroblastoma, breast cancer, ovariancancer, lung cancer, rhabdomyosarcoma, small-cell lung tumors, primarybrain tumors, stomach cancer, colon cancer, pancreatic cancer, urinarybladder cancer, testicular cancer, thyroid cancer, neuroblastoma,esophageal cancer, genitourinary tract cancer, cervical cancer,endometrial cancer, adrenal cortical cancer, or prostate cancer.

Preferably, such assay for circulating tumor cells is performed usingantibodies directed against target peptides wherein said antibodies aredetectably labeled. In one particular embodiment, such assay forcirculating tumor cells is performed using immunofluorescence assays viamonoclonal antibodies directed against target peptides and is preferablyperformed on peripheral blood of patients.

The presence of circulating tumor cells in blood can be correlated witha metastatic tumor disease or a risk for a metastatic tumor disease andwith poor outcome and lower survival rate.

The most reliable method currently available for CTC detection isautomated digital microscopy (ADM) using image analysis for recognitionof immunocytochemically labeled tumor cells. ADM, however, isdisadvantaged by its very slow scan speeds of 800 cells/sec. Kraeft etal, Clin Cancer Res 10: 3020-8, 2004. The ADM scan speed is constrainedby the latency associated with stepping the sample many times due to thelimited field of view.

To circumvent this speed constraint, several CTC enrichment technologieshave been developed to reduce the total number of cells that needscanning. To date the most successful of these enrichment approaches isimmunomagnetic enrichment (IME). Smimov et al, Cancer Res 65: 4993-7,2005; Allard et al, Clin Cancer Res 10: 6897-904, 2004; Cristofanilli etal, N Engl J Med 351: 781-91, 2004. In most implementations of IME,monoclonal antibodies conjugated to small magnetic beads target theepithelial cell adhesion molecule, EpCAM. The beads are then manipulatedin magnetic fields for enrichment.

A further aspect of the invention relates to a method of detectingmetastatic colon cancer cells or metastatic gastric cancer cells in apatient comprising the detection of and/or determination of the quantityof (i) a nucleic acid which comprises the nucleic acid sequence of atumor nucleic acid identified according to the invention/a nucleic acidwhich codes for a peptide comprising the amino acid sequence of a tumorantigen identified according to the invention, and/or (ii) a peptidecomprising the amino acid sequence of a tumor antigen identifiedaccording to the invention or of a tumor antigen peptide derived fromsaid tumor antigen, in a biological sample isolated from a tissue ororgan of said patient having a tumor wherein the cells when the tissueor organ is free of tumors do not substantially express said nucleicacid or peptide.

Thus, in the methods of detecting metastatic colon cancer cells ormetastatic gastric cancer cells tumor nucleic acids identified accordingto the invention and/or tumor antigens identified according to theinvention or tumor antigen peptides derived therefrom are used as targetmolecules to identify tumor cells which are characterized by thepresence of said target molecules. These cells are likely to representmetastatic colon cancer cells or metastatic gastric cancer cells. In oneembodiment, the nucleic acid or the peptide is detected or its quantitydetermined in situ in a cell, preferably a tumor cell.

In one embodiment, the peptide is detected or its quantity determined insitu on the surface of a cell, either incorporated in the plasmamembrane or in a complex with MHC class I or class II, preferably MHCclass I. Means for accomplishing said detection and/or determination ofthe quantity of such target molecules are described herein and will beapparent to the skilled person.

According to the invention a nucleic acid and/or a peptide is notsubstantially expressed if the level of expression is lower compared toexpression in colon cells and/or stomach cells or colon tissue and/orstomach tissue. Preferably, the level of expression is less than 10%,preferably less than 5%, 3%, 2%, 1%, 0.5%, 0.1% or 0.05% or even lowercompared to colon cells and/or stomach cells or colon tissue and/orstomach tissue. Preferably, a nucleic acid and/or a peptide is notsubstantially expressed if the level of expression is below thedetection limit.

Preferably, the tissue is a tissue other than colon tissue or gastrictissue. Preferably, said tissue is tissue of small intestine, brain,breast, liver, lung, pancreas, kidney, prostate, spleen, lymph node,endometrium, esophagus, placenta, ovary, testis, uterus, skin, thymus,bladder, muscle and cervix.

Preferably, the tissue or organ has already been diagnosed as beingaffected by a tumor disease by visual inspection or culture testing ofcells of said tissue organ.

In one aspect of the method, the presence of said nucleic acid accordingto (i) and/or said peptide according to (ii) in said biological sampleor a quantity of said nucleic acid and/or peptide in said biologicalsample which is increased compared to a reference level indicates thepresence of or risk for metastatic colon cancer cells or metastaticgastric cancer cells in said tissue or organ. The presence of metastaticcolon cancer cells or metastatic gastric cancer cells in said tissue ororgan may also indicate the presence of or risk for colorectal cancer,in particular colon cancer, and gastric cancer in said patient.

A positive diagnosis of metastatic colon cancer cells or metastaticgastric cancer cells may indicate that the tumor of the tissue or organfrom which the biological sample has been isolated is amenable to themethods of treatment described herein.

A further object of this invention relates to diagnostic test kitsuseful in the methods for diagnosis, detection or monitoring and in themethods for detecting circulating tumor cells and/or in the methods ofdetecting metastatic colon cancer cells or metastatic gastric cancercells of the invention. These kits in one embodiment comprise a ligandthat specifically binds to a target molecule as defined above and,optionally, a detectable label, e.g. indicator enzymes, a radiolabels,fluorophores, or paramagnetic particles. In a particular embodiment, theligand comprises nucleic acid primers or probes specific for targetnucleic acids as described above, or an antibody or a derivativethereof, specific for a target peptide as described above. Kits mayinclude informative pamphlets, for example, pamphlets informing one howto use reagents to practice a method disclosed herein.

In a further aspect, the invention relates to a recombinant nucleic acidmolecule, in particular DNA or RNA molecule, which comprises a nucleicacid which codes for a peptide comprising the amino acid sequence of atumor antigen or of a tumor antigen peptide derived from said tumorantigen.

The invention also relates to host cells which comprise a recombinantnucleic acid molecule of the invention. Preferably, such host cellsexpress the encoded peptide.

The host cell may be a recombinant cell and may secrete the encodedpeptide, may express it on the surface and preferably may additionallyexpress an MHC molecule which binds to said peptide or a processionproduct thereof. In one embodiment, the host cell expresses the MHCmolecule endogenously. In a further embodiment, the host cell expressesthe MHC molecule and/or the peptide or the procession product thereof ina recombinant manner. The host cell is preferably nonproliferative. In apreferred embodiment, the host cell is an antigen-presenting cell, inparticular a dendritic cell, a monocyte or a macrophage.

In a further aspect, the invention relates to a peptide comprising theamino acid sequence of a tumor antigen identified according to theinvention or of a tumor antigen peptide derived from said tumor antigen,or a derivative of said peptide.

In a further aspect, the invention relates to an agent which binds to apeptide comprising the amino acid sequence of a tumor antigen identifiedaccording to the invention or of a tumor antigen peptide derived fromsaid tumor antigen, or a derivative of said peptide. In a preferredembodiment, the agent is a protein or peptide, in particular anantibody, a T cell receptor or an MHC molecule. In further embodiments,the antibody is a monoclonal, chimeric, human or humanized antibody, anantibody produced by combinatory techniques, a fragment of an antibody,or a synthetic antibody.

The invention furthermore relates to a conjugate between an agent of theinvention which binds to a peptide comprising the amino acid sequence ofa tumor antigen identified according to the invention or of a tumorantigen peptide derived from said tumor antigen, or a derivative of saidpeptide and a therapeutic effector moiety or a detectable label.

DETAILED DESCRIPTION OF THE INVENTION

Some aspects of the present invention envision the immunotherapy oftumor diseases, in particular cancer diseases, utilizing the tumornucleic acids and tumor antigens identified according to the inventionby means of active or passive immunotherapeutic approaches which can besummarized as follows:

Immunotherapy

I. Active immunotherapy (“Cancer vaccines”)Immunisation with:i) antigen or peptide (native or modified)ii) nucleic acid encoding the antigen or peptideiii) recombinant cells encoding the antigen or peptideiv) recombinant viruses encoding the antigen or peptidev) antigen presenting cells pulsed with antigen or peptide (native ormodified) or transfected with nucleic acids encoding the antigen orpeptideII. Passive immunotherapy (“Adoptive immunotherapy”)vi) Transfer of antibodies or T cell receptors that recognise antigenvii) Transfer of cells sensitized in vitro to antigen (bulk or clonedpopulations)viii) Transfer of effector cells (or stem cells) transduced with nucleicacids encoding T cell receptors that recognise antigen and preferablyare responsive to tumor-specific class I MHC presented peptides

In the past few years, much attention has been given to the role of CD8+T cells in tumor immunity. Tumour-specific CD8+CTLs have been shown tobe capable of lysing tumour cells directly and eradicating tumour massesin vivo in animal models. However, CD4+ T cells are also thought to playa critical role and it may be that optimal cancer vaccines require theparticipation of both CD4+ and CD8+ T cells.

Immunisation with intact or substantially intact tumor antigen has thepotential advantage of simultaneously immunising against both class Iand class II epitopes but requires extensive and time-consuming effortsto purify large amounts of tumor antigen. The identification of MHCclass I and class II peptides within a tumor antigen makes it possibleto immunise with high levels of pure synthetic peptide. The peptideapproach also has the advantage that one can choose between a MHC classI and a class II type response (or mixture) by choosing which epitopesto use. Immunisation with peptide also means that subdominant and/orcryptic epitopes can be chosen (as the need for antigen processing maybe bypassed or reduced to a “trimming” role) in order to stimulate adifferent subset of T cells. Also the peptide may be modified (forexample at their HLA class I or II anchor sites) to increase itsimmunogenicity.

The invention relates to tumor-specific class I MHC presented peptidesand methods of using the same, as well as cytotoxic T lymphocytes (CTLs)responsive to tumor-specific class I MHC presented peptides and methodsof using the same.

In one aspect, the invention provides anti-tumor vaccines capable ofstimulating a cellular response against a tumor characterized bypresentation of a tumor antigen identified according to the inventionwith class I MHC. The anti-tumor vaccines of the invention preferablycomprise a tumor antigen peptide, or a tumor antigen peptide nucleicacid.

The invention also encompasses the use of nucleic acids encoding one ormore of the tumor antigens identified according to the invention or oneor more tumor antigen peptides derived therefrom. It is anticipated thatthe antigens or peptides so encoded are effective as therapeutic orprophylactic anti-tumor vaccines. For example, a particular contemplatedapplication of these nucleic acids involves the induction of a cellularresponse such as a CTL response and/or a humoral immune response againstsuch antigens.

Immunization with plasmid DNA can elicit antigen-specific immuneresponses consisting of CD8+ T cells, CD4+ T cells, and antibodies. DNAcan be administered by the gene gun method of immunization. In gene gunimmunization, plasmid DNA may be coated onto gold particles followed bydelivery of the DNA-coated particles into the skin by a high-pressure,helium-driven gene gun.

Advances in molecular biology have made it possible to constructrecombinant viruses that encode tumor antigens or tumor antigen peptidesas described herein.

Several recombinant viral vaccines have been used up to now.

Several viral vectors have shown promising results with regard to theirpotential to enhance immunotherapy of malignant diseases. Replicationcompetent and replication incompetent viruses can be used, with thelatter group being preferred. Herpes virus, adenovirus, vaccinia,reovirus, and New Castle Disease viruses are examples of preferredviruses useful according to the present invention.

Antigen presenting cells (APC) such as dendritic cells (DCs) can beloaded with either MHC class I-presented peptides or tumor lysate, ortransduced with nucleic acid such as by transduction using adenovirusencoding a tumor antigen.

In a preferred embodiment, an anti-tumor vaccine of the inventioncomprises an APC loaded with tumor antigen peptide. In this respect,protocols may rely on in vitro culture/differentiation of DCsmanipulated in such a way that they artificially present tumor antigenpeptide. Production of genetically engineered DCs may involveintroduction of nucleic acids encoding tumor antigens or tumor antigenpeptides into DCs. Transfection of DCs with mRNA is a promisingantigen-loading technique of stimulating strong antitumor immunity.

Dendritic cells (DCs) are leukocyte populations that present antigenscaptured in peripheral tissues to T cells via both MHC class II and Iantigen presentation pathways. It is well known that DCs are potentinducers of immune responses and the activation of these cells is acritical step for the induction of antitumoral immunity. DC maturationis referred to as the status of DC activation at which suchantigen-presenting DCs leads to T-cell priming, while its presentationby immature DCs results in tolerance. DC maturation is chiefly caused bybiomolecules with microbial features detected by innate receptors(bacterial DNA, viral RNA, endotoxin, etc), pro-inflammatory cytokines(TNF, IL-1, IFNs), ligation of CD40 on the DC surface by CD40L, andsubstances released from cells undergoing stressful cell death. The DCscan be derived by culturing bone marrow cells in vitro with cytokines,such as granulocyte-macrophage colony-stimulating factor (GM-CSF) andtumor necrosis factor alpha.

Yet another embodiment of the invention comprises the preparation ofantibodies, preferably monoclonal antibodies against a target antigen asdefined above. Such monoclonal antibodies may be produced byconventional methods and include fragments or derivatives thereof,including, without limitation, human monoclonal antibodies, humanizedmonoclonal antibodies, chimeric monoclonal antibodies, single chainantibodies, e.g., scFv's and antigen-binding antibody fragments such asFab and Fab′ fragments. Methods for the preparation of monoclonalantibodies are known in the art. In general, the preparation ofmonoclonal antibodies comprises immunization of an appropriate host withthe subject antigens, isolation of immune cells therefrom, use of suchimmune cells to isolate monoclonal antibodies and screening formonoclonal antibodies that specifically bind to either of such antigens.Antibody fragments may be prepared by known methods, e.g., enzymaticcleavage of monoclonal antibodies.

These monoclonal antibodies and fragments are useful for passiveanti-tumor immunotherapy, or may be attached to therapeutic effectormoieties, e.g., radiolabels, cytotoxins, therapeutic enzymes, agentsthat induce apoptosis, and the like in order to provide for targetedcytotoxicity, i.e., killing of tumor cells. In one embodiment of thepresent invention, such antibodies or fragments are administered inlabeled or unlabeled form, alone or in conjunction with othertherapeutics, e.g., chemotherapeutics such as cisplatin, methotrexate,adriamycin, and the like suitable for cancer therapy.

If used for passive anti-tumor immunotherapy, antibodies may or may notbe attached to therapeutic effector moieties. Preferably the antibodiesdescribed herein mediate killing of cells by inducing complementdependent cytotoxicity (CDC) mediated lysis, antibody dependent cellularcytotoxicity (ADCC) mediated lysis, apoptosis, homotypic adhesion,and/or phagocytosis, preferably by inducing CDC mediated lysis and/orADCC mediated lysis. The antibodies described herein preferably interactwith components of the immune system, preferably through ADCC or CDC.However, antibodies of the invention may also exert an effect simply bybinding to tumor antigens on the cell surface, thus, e.g. blockingproliferation of the cells.

ADCC describes the cell-killing ability of effector cells as describedherein, in particular lymphocytes, which preferably requires the targetcell being marked by an antibody.

ADCC preferably occurs when antibodies bind to antigens on tumor cellsand the antibody Fc domains engage Fc receptors (FcR) on the surface ofimmune effector cells. Several families of Fc receptors have beenidentified, and specific cell populations characteristically expressdefined Fc receptors. ADCC can be viewed as a mechanism to directlyinduce a variable degree of immediate tumor destruction that also leadsto antigen presentation and the induction of tumor-directed T-cellresponses. Preferably, in vivo induction of ADCC will lead totumor-directed T-cell responses and host-derived antibody responses.

CDC is another cell-killing method that can be directed by antibodies.IgM is the most effective isotype for complement activation. IgG1 andIgG3 are also both very effective at directing CDC via the classicalcomplement-activation pathway. Preferably, in this cascade, theformation of antigen-antibody complexes results in the uncloaking ofmultiple C1q binding sites in close proximity on the C_(H)2 domains ofparticipating antibody molecules such as IgG molecules (C1q is one ofthree subcomponents of complement C1). Preferably these uncloaked C1qbinding sites convert the previously low-affinity C1q-IgG interaction toone of high avidity, which triggers a cascade of events involving aseries of other complement proteins and leads to the proteolytic releaseof the effector-cell chemotactic/activating agents C3a and C5a.Preferably, the complement cascade ends in the formation of a membraneattack complex, which creates pores in the cell membrane that facilitatefree passage of water and solutes into and out of the cell and may leadto apoptosis.

Passive immunotherapy with immune cells (optionally geneticallymodified) capable of recognizing tumor antigens is effective inmediating the regression of cancer in selected patients. Thesetechniques may be based on ex-vivo reactivation and expansion of clonedor polyclonal cultures of tumor reactive T cells. After culture, T cellsmay be reinfused into the patient along with IL-2. In vitro techniqueshave been developed in which human lymphocytes are sensitized in vitroto tumor antigen peptides presented on antigen presenting cells. Byrepetitive in vitro stimulation cells can be derived with a greatcapacity to recognize human tumor antigens. The adoptive transfer ofthese cells may be more effective in mediating tumor regression in vivothan are conventionally grown cells.

In one embodiment, autologous cytotoxic lymphocytes or tumorinfiltrating lymphocytes may be obtained from a patient with cancer. Thelymphocytes may be grown in culture and tumor antigen-responsive CTLsexpanded by culturing in the presence of tumor antigen peptide presentedwith MHC class I, alone or in combination with at least oneimmunomodulatory agent, preferably additionally with cytokines. Thetumor antigen-responsive CTLs are then infused back into the patient inan amount effective to reduce or eliminate the tumors in the patient.

Patients could be pre-stimulated with an anti-tumor peptide vaccineprior lymphocyte harvest if the existing response was inadequate. It isexpected that the adoptively transferred CTLs would survive best withIL-2 infusion at low to intermediate doses.

By “tumor antigen-responsive CTL” is meant a CD8+ T cell that isresponsive to a tumor antigen peptide derived from said tumor antigen,which is presented with class I MHC, e.g. on the surface of tumor cells.

According to the invention, CTL responsiveness may include sustainedcalcium flux, cell division, production of cytokines such as IFN-gammaand TNF-alpha, upregulation of activation markers such as CD44 and CD69,and specific cytolytic killing of tumor antigen expressing target cells.CTL responsiveness may also be determined using an artificial reporterthat accurately indicates CTL responsiveness.

By “tumor antigen peptide” or “tumor antigen peptide derived from atumor antigen” is meant an oligopeptide or polypeptide comprising anamino acid sequence substantially corresponding to the amino acidsequence of a fragment or peptide of a tumor antigen identifiedaccording to the present invention. Preferably, a tumor antigen peptideis capable of stimulating a cellular response against a tumorcharacterized by presentation of a tumor antigen identified herein withclass I MHC and preferably a tumor antigen-responsive CTL and/or ofeliciting antibodies that specifically bind to a tumor antigenidentified according to the present invention when used itself orattached to an immunogenic carrier. A tumor antigen peptide according tothe invention preferably is a peptide comprising a sequencesubstantially corresponding to the sequence of a fragment of the aminoacid sequence according to SEQ ID NO: 2 of the sequence listing or is aderivative of said peptide. A tumor antigen peptide may be of anylength.

If a tumor antigen peptide is to be presented directly, i.e. withoutprocessing, in particular without cleavage, it has a length which issuitable for binding to an MHC molecule, in particular a class I MHCmolecule, and preferably is 7-20 amino acids in length, more preferably7-12 amino acids in length, more preferably 8-11 amino acids in length,in particular 9 or 10 amino acids in length. Preferably the sequence ofa tumor antigen peptide which is to be presented directly is derivedfrom the amino acid sequence of a tumor antigen identified according tothe invention, i.e. its sequence substantially corresponds and ispreferably completely identical to a fragment of a tumor antigenidentified according to the invention. If a tumor antigen peptide is tobe presented following processing, in particular following cleavage, thepeptide produced by processing has a length which is suitable forbinding to an MHC molecule, in particular a class I MHC molecule, andpreferably is 7-20 amino acids in length, more preferably 7-12 aminoacids in length, more preferably 8-11 amino acids in length, inparticular 9 or 10 amino acids in length. Preferably the sequence of thepeptide which is to be presented following processing is derived fromthe amino acid sequence of a tumor antigen identified according to theinvention, i.e. its sequence substantially corresponds and is preferablycompletely identical to a fragment of a tumor antigen identifiedaccording to the invention. Thus, a tumor antigen peptide according tothe invention in one embodiment comprises a sequence of 7-20 amino acidsin length, more preferably 7-12 amino acids in length, more preferably8-11 amino acids in length, in particular 9 or 10 amino acids in lengthwhich substantially corresponds and is preferably completely identicalto a fragment of a tumor antigen identified according to the inventionand following processing of the tumor antigen peptide makes up thepresented peptide. However, the tumor antigen peptide may also comprisea sequence which substantially corresponds and preferably is completelyidentical to a fragment of a tumor antigen identified according to theinvention which is even longer than the above stated sequence. In oneembodiment, a tumor antigen peptide may comprise the entire sequence ofa tumor antigen identified according to the invention.

Preferably, a tumor antigen peptide may be presented, directly orfollowing processing, with class I MHC molecules, and when so presentedis capable of stimulating a tumor antigen-responsive CTL. Peptideshaving amino acid sequences substantially corresponding to a sequence ofa peptide which is presented by the class I MHC may differ at one ormore residues that are not essential for TCR recognition of the peptideas presented by the class I MHC, or for peptide binding to MHC. Suchsubstantially corresponding peptides are also capable of stimulating atumor antigen-responsive CTL. Peptides having amino acid sequencesdiffering from a presented peptide at residues that do not affect TCRrecognition but improve the stability of binding to MHC may improve theimmunogenicity of the tumor antigen peptide, and may be referred toherein as “optimized peptides”. Using existing knowledge about which ofthese residues may be more likely to affect binding either to the MHC orto the TCR, a rational approach to the design of substantiallycorresponding peptides may be employed. Resulting peptides that arefunctional are contemplated as tumor antigen peptides.

By “immunoreactive cell” is meant a cell which can mature into an immunecell (such as a B cell, a helper T cell, or a CTL) upon appropriatestimulation. Thus immunoreactive cells include CD34+ hematopoietic stemcells, immature T cells and immature B cells. When it is desired toproduce CTLs which recognize a tumor antigen, the immunoreactive cell iscontacted with a cell which presents the tumor antigen or a tumorantigen peptide derived from said tumor antigen under conditionsfavoring production, differentiation and/or selection of CTLs.

By “cell characterized by presentation of a tumor antigen with class IMHC” or “cell presenting a tumor antigen with class I MHC” or similarexpressions is meant a cell such as a tumor cell or an antigenpresenting cell presenting the tumor antigen it expresses or a fragmentderived from said tumor antigen, e.g. by processing of the tumorantigen, in the context of MHC Class I molecules. Similarly, the term“tumor characterized by presentation of a tumor antigen with class IMHC” denotes a tumor comprising cells characterized by presentation of atumor antigen with class I MHC.

By “fragment of a tumor antigen identified according to the inventionwhich is presented” or similar expressions is meant that the fragmentcan be presented by MHC class I or class II, preferably MHC class I,e.g. when added directly to antigen presenting cells. In one embodiment,the fragment is a fragment which is naturally presented by cellsexpressing a tumor antigen identified according to the invention, e.g.tumor cells.

By “cell that recognizes a tumor antigen or a tumor antigen peptidederived from said tumor antigen” or “immunoreactive cell that recognizesa tumor antigen or a tumor antigen peptide derived from said tumorantigen” or similar expressions is meant a cell that is able torecognize said tumor antigen or a tumor antigen peptide derived fromsaid tumor antigen with some degree of specificity, in particular ifpresented in the context of MHC molecules such as on the surface ofantigen presenting cells or tumor cells. Preferably, said recognitionenables the cell that recognizes a tumor antigen or a tumor antigenpeptide derived from said tumor antigen to be responsive. If the cell isa helper T cell (CD4+ T cell) bearing receptors that recognize a tumorantigen or a tumor antigen peptide derived from said tumor antigen inthe context of MHC class II molecules such responsiveness may involvethe release of cytokines and/or the activation of CD8+ lymphocytes(CTLs) and/or B cells. If the cell is a CTL such responsiveness mayinvolve the elimination of cells presented in the context of MHC class Imolecules, i.e. cells characterized by presentation of a tumor antigenwith class I MHC, for example via apoptosis or perforin-mediated celllysis. Such CTL that recognizes a tumor antigen or a tumor antigenpeptide derived from said tumor antigen and are responsive are alsotermed “tumor antigen-responsive CTL” herein. If the cell is a B cellsuch immune such responsiveness may involve the release ofimmunoglobulins.

By “T cell receptor that recognizes a tumor antigen or a tumor antigenpeptide derived from said tumor antigen” is meant a T cell receptor thatis able to recognize said tumor antigen or a tumor antigen peptidederived from said tumor antigen with some degree of specificity, inparticular if presented in the context of MHC molecules. Preferably,said recognition enables the cell carrying the T cell receptor thatrecognizes a tumor antigen or a tumor antigen peptide derived from saidtumor antigen to be responsive as outlined above.

A “cellular response against a tumor antigen” is meant to include acellular response directed to cells characterized by presentation of atumor antigen with class I or class II MHC. The cellular responserelates to cells called T cells or T lymphocytes which act as either‘helpers’ or ‘killers’. The helper T cells (also termed CD4+ T cells)play a central role by regulating the immune response and the killercells (also termed cytotoxic T cells, cytolytic T cells, CD8+ T cells orCTLs) kill tumor cells, preventing the production of more tumor cells.Although both arms of the immune response are thought to be necessary,the CTL response may be more important for controlling cancer.

According to the invention, a “reference” such as a reference sample orreference organism may be used to correlate and compare the resultsobtained in the methods of the invention from a test sample or testorganism, i.e. a patient. Typically the reference organism is a healthyorganism, in particular an organism which does not suffer from a tumordisease.

A “reference value” or “reference level” can be determined from areference empirically by measuring a sufficiently large number ofreferences. Preferably the reference value is determined by measuring atleast 2, preferably at least 3, preferably at least 5, preferably atleast 8, preferably at least 12, preferably at least 20, preferably atleast 30, preferably at least 50, or preferably at least 100 references.

According to the invention, the term “binding” preferably relates to aspecific binding. “Specific binding” means that an agent such as anantibody binds stronger to a target such as an epitope for which it isspecific compared to the binding to another target. An agent bindsstronger to a first target compared to a second target if it binds tothe first target with a dissociation constant (K_(D)) which is lowerthan the dissociation constant for the second target. Preferably thedissociation constant (K_(D)) for the target to which the agent bindsspecifically is more than 10²-fold, 10³-fold, 10⁴-fold, 10⁵-fold,10⁶-fold, 10⁷-fold, 10⁸-fold, 10⁹-fold, or 10¹⁰-fold lower than thedissociation constant (K_(D)) for the target to which the agent does notbind specifically.

According to the invention, a nucleic acid is preferablydeoxyribonucleic acid (DNA) or ribonucleic acid (RNA). Nucleic acidscomprise according to the invention genomic DNA, cDNA, mRNA,recombinantly produced and chemically synthesized molecules. Accordingto the invention, a nucleic acid may be present as a single-stranded ordouble-stranded and linear or covalently circularly closed molecule.

The terms “tumor nucleic acid identified according to the invention” and“nucleic acid encoding a tumor antigen identified according to theinvention” have similar meanings.

As used herein, the term “RNA” means a molecule comprising at least oneribonucleotide residue. By “ribonucleotide” is meant a nucleotide with ahydroxyl group at the 2′-position of a beta-D-ribo-furanose moiety. Theterm includes double stranded RNA, single stranded RNA, isolated RNAsuch as partially purified RNA, essentially pure RNA, synthetic RNA,recombinantly produced RNA, as well as altered RNA that differs fromnaturally occurring RNA by the addition, deletion, substitution and/oralteration of one or more nucleotides. Such alterations can includeaddition of non-nucleotide material, such as to the end(s) of a RNA orinternally, for example at one or more nucleotides of the RNA.Nucleotides in RNA molecules can also comprise non-standard nucleotides,such as non-naturally occurring nucleotides or chemically synthesizednucleotides or deoxynucleotides. These altered RNAs can be referred toas analogs or analogs of naturally-occurring RNA.

If reference is made herein to the detection of or the determination ofthe quantity of a nucleic acid, the nucleic acid which is actually to bedetected or the quantity of which is actually to be determined ispreferably mRNA. However, it should be understood that this may alsoinclude embodiments wherein mRNA is detected or the quantity of mRNA isdetermined indirectly. For example, mRNA may be transformed into cDNAand the cDNA detected or its quantity determined. mRNA is given hereinas the cDNA equivalent. One skilled in the art would understand that thecDNA sequence is equivalent to the mRNA sequence, and can be used forthe same purpose herein, e.g., the generation of probes hybridizing tothe nucleic acid to be detected. Thus, if reference is made herein tothe sequences shown in the sequence listing this is also to include theRNA equivalents of said sequences.

The nucleic acids described according to the invention have preferablybeen isolated. The term “isolated nucleic acid” means according to theinvention that the nucleic acid was (i) amplified in vitro, for exampleby polymerase chain reaction (PCR), (ii) recombinantly produced bycloning, (iii) purified, for example by cleavage and gel-electrophoreticfractionation, or (iv) synthesized, for example by chemical synthesis.An isolated nucleic acid is a nucleic acid which is available formanipulation by recombinant. DNA techniques.

The term “variant” with respect to, for example, nucleic acid and aminoacid sequences, according to the invention includes any variants, inparticular mutants, splice variants, conformations, isoforms, allelicvariants, species variants and species homologs, in particular thosewhich are naturally present. An allelic variant relates to an alterationin the normal sequence of a gene, the significance of which is oftenunclear. Complete gene sequencing often identifies numerous allelicvariants for a given gene. A species homolog is a nucleic acid or aminoacid sequence with a different species of origin from that of a givennucleic acid or amino acid sequence.

With respect to nucleic acid molecules, the term “variant” includesdegenerate nucleic acid sequences, wherein a degenerate nucleic acidaccording to the invention is a nucleic acid that differs from areference nucleic acid in codon sequence due to the degeneracy of thegenetic code.

Furthermore, a “variant” of a specific nucleic acid sequence accordingto the invention includes nucleic acid sequences comprising single ormultiple such as at least 2, at least 4, or at least 6 and preferably upto 3, up to 4, up to 5, up to 6, up to 10, up to 15, or up to 20nucleotide substitutions, deletions and/or additions.

Preferably the degree of identity between a given nucleic acid sequenceand a nucleic acid sequence which is a variant of said given nucleicacid sequence will be at least 70%, preferably at least 75%, preferablyat least 80%, more preferably at least 85%, even more preferably atleast 90% or most preferably at least 95%, 96%, 97%, 98% or 99%. Thedegree of identity is preferably given for a region of at least about30, at least about 50, at least about 70, at least about 90, at leastabout 100, at least about 150, at least about 200, at least about 250,at least about 300, or at least about 400 nucleotides. In preferredembodiments, the degree of identity is given for the entire length ofthe reference nucleic acid sequence.

“Sequence similarity” indicates the percentage of amino acids thateither are identical or that represent conservative amino acidsubstitutions. “Sequence identity” between two polypeptide or nucleicacid sequences indicates the percentage of amino acids or nucleotidesthat are identical between the sequences.

The term “percentage identity” is intended to denote a percentage ofnucleotides or of amino acid residues which are identical between thetwo sequences to be compared, obtained after the best alignment, thispercentage being purely statistical and the differences between the twosequences being distributed randomly and over their entire length.Sequence comparisons between two nucleotide or amino acid sequences areconventionally carried out by comparing these sequences after havingaligned them optimally, said comparison being carried out by segment orby “window of comparison” in order to identify and compare local regionsof sequence similarity. The optimal alignment of the sequences forcomparison may be produced, besides manually, by means of the localhomology algorithm of Smith and Waterman, 1981, Ads App. Math. 2, 482,by means of the local homology algorithm of Neddleman and Wunsch, 1970,J. Mol. Biol. 48, 443, by means of the similarity search method ofPearson and Lipman, 1988, Proc. Natl. Acad. Sci. USA 85, 2444, or bymeans of computer programs which use these algorithms (GAP, BESTFIT,FASTA, BLAST P, BLAST N and TFASTA in Wisconsin Genetics SoftwarePackage, Genetics Computer Group, 575 Science Drive, Madison, Wis.).

The percentage identity is calculated by determining the number ofidentical positions between the two sequences being compared, dividingthis number by the number of positions compared and multiplying theresult obtained by 100 so as to obtain the percentage identity betweenthese two sequences.

A nucleic acid is “capable of hybridizing” or “hybridizes” to anothernucleic acid if the two sequences are complementary with one another. Anucleic acid is “complementary” to another nucleic acid if the twosequences are capable of forming a stable duplex with one another.According to the invention, hybridization is preferably carried outunder conditions which allow specific hybridization betweenpolynucleotides (stringent conditions). Stringent conditions aredescribed, for example, in Molecular Cloning: A Laboratory Manual, J.Sambrook et al., Editors, 2nd Edition, Cold Spring Harbor Laboratorypress, Cold Spring Harbor, N.Y., 1989 or Current Protocols in MolecularBiology, F. M. Ausubel et al., Editors, John Wiley & Sons, Inc., NewYork and refer, for example, to hybridization at 65° C. in hybridizationbuffer (3.5×SSC, 0.02% Ficoll, 0.02% polyvinylpyrrolidone, 0.02% bovineserum albumin, 2.5 mM NaH₂PO₄ (pH 7), 0.5% SDS, 2 mM EDTA). SSC is 0.15M sodium chloride/0.15 M sodium citrate, pH 7. After hybridization, themembrane to which the DNA has been transferred is washed, for example,in 2×SSC at room temperature and then in 0.1-0.5×SSC/0.1×SDS attemperatures of up to 68° C.

A percent complementarity indicates the percentage of contiguousresidues in a nucleic acid molecule that can form hydrogen bonds (e.g.,Watson-Crick base pairing) with a second nucleic acid sequence (e.g., 5,6, 7, 8, 9, 10 out of 10 being 50%, 60%, 70%, 80%, 90%, and 100%complementary). “Perfectly complementary” or “fully complementary” meansthat all the contiguous residues of a nucleic acid sequence willhydrogen bond with the same number of contiguous residues in a secondnucleic acid sequence. Preferably, the degree of complementarityaccording to the invention is at least 70%, preferably at least 75%,preferably at least 80%, more preferably at least 85%, even morepreferably at least 90% or most preferably at least 95%, 96%, 97%, 98%or 99%. Most preferably, the degree of complementarity according to theinvention is 100%.

The term “derivative” comprises any chemical derivatization of a nucleicacid on a nucleotide base, on the sugar or on the phosphate. The term“derivative” also comprises nucleic acids which contain nucleotides andnucleotide analogs not occurring naturally. Preferably, a derivatizationof a nucleic acid increases its stability.

Nucleic acids coding for tumor antigens or tumor antigen peptides may,according to the invention, be present alone or in combination withother nucleic acids, in particular heterologous nucleic acids.Preferably, a nucleic acid coding for a tumor antigen or tumor antigenpeptide expresses said tumor antigen or tumor antigen peptide. Inpreferred embodiments, a nucleic acid is functionally linked toexpression control sequences or regulatory sequences which may behomologous or heterologous with respect to said nucleic acid. A codingsequence and a regulatory sequence are “functionally” linked to oneanother, if they are covalently linked to one another in such a way thatexpression or transcription of said coding sequence is under the controlor under the influence of said regulatory sequence. If the codingsequence is to be translated into a functional protein, then, with aregulatory sequence functionally linked to said coding sequence,induction of said regulatory sequence results in transcription of saidcoding sequence, without causing a frame shift in the coding sequence orsaid coding sequence not being capable of being translated into thedesired protein or peptide.

The term “expression control sequence” or “regulatory sequence”comprises according to the invention promoters, enhancers and othercontrol elements which regulate expression of a gene. In particularembodiments of the invention, the expression control sequences can beregulated. The exact structure of regulatory sequences may vary as afunction of the species or cell type, but generally comprises 5′untranscribed and 5′ untranslated sequences which are involved ininitiation of transcription and translation, respectively, such as TATAbox, capping sequence, CAAT sequence, and the like. More specifically,5′ untranscribed regulatory sequences comprise a promoter region whichincludes a promoter sequence for transcriptional control of thefunctionally linked gene. Regulatory sequences may also compriseenhancer sequences or upstream activator sequences.

According to the invention, a nucleic acid may furthermore be present incombination with another nucleic acid which codes for a peptidecontrolling secretion of the protein or peptide encoded by said nucleicacid from a host cell. According to the invention, a nucleic acid mayalso be present in combination with another nucleic acid which codes fora peptide causing the encoded protein or peptide to be anchored on thecell membrane of the host cell or compartmentalized into particularorganelles of said cell. Similarly, a combination with a nucleic acid ispossible which represents a reporter gene or any “tag”.

In a preferred embodiment, a recombinant nucleic acid molecule isaccording to the invention a vector, where appropriate with a promoter,which controls expression of a nucleic acid, for example a nucleic acidcoding for a tumor antigen identified according to the invention. Theterm “vector” is used here in its most general meaning and comprises anyintermediary vehicle for a nucleic acid which enables said nucleic acid,for example, to be introduced into prokaryotic and/or eukaryotic cellsand, where appropriate, to be integrated into a genome. Vectors of thiskind are preferably replicated and/or expressed in the cells. Anintermediary vehicle may be adapted, for example, to the use inelectroporation, in bombardment with microprojectiles, in liposomaladministration, in the transfer with the aid of agrobacteria or ininsertion via DNA or RNA viruses. Vectors comprise plasmids, phagemids,bacteriophages or viral genomes.

The nucleic acids coding for a tumor antigen identified according to theinvention may be used for transfection of host cells. Nucleic acids heremean both recombinant DNA and RNA. Recombinant RNA may be prepared byin-vitro transcription of a DNA template. Furthermore, it may bemodified by stabilizing sequences, capping and polyadenylation prior toapplication.

According to the invention, the term “host cell” relates to any cellwhich can be transformed or transfected with an exogenous nucleic acid.The term “host cells” comprises according to the invention prokaryotic(e.g. E. coli) or eukaryotic cells (e.g. dendritic cells, B cells, CHOcells, COS cells, K562 cells, yeast cells and insect cells). Particularpreference is given to mammalian cells such as cells from humans, mice,hamsters, pigs, goats, primates. The cells may be derived from amultiplicity of tissue types and comprise primary cells and cell lines.Specific examples comprise keratinocytes, peripheral blood leukocytes,stem cells of the bone marrow and embryonic stem cells. In furtherembodiments, the host cell is an antigen-presenting cell, in particulara dendritic cell, monocyte or a macrophage. A nucleic acid may bepresent in the host cell in the form of a single copy or of two or morecopies and, in one embodiment, is expressed in the host cell.

According to the invention, the term “expression” is used in its mostgeneral meaning and comprises the production of RNA or of RNA andprotein. It also comprises partial expression of nucleic acids.Furthermore, expression may be carried out transiently or stably.Preferred expression systems in mammalian cells comprise pcDNA3.1,pcDNA3.3 and pRc/CMV (Invitrogen, Carlsbad, Calif.), which contain aselectable marker such as a gene imparting resistance to G418 (and thusenabling stably transfected cell lines to be selected) and theenhancer-promoter sequences of cytomegalovirus (CMV).

In those cases of the invention in which an MHC molecule presents atumor antigen or a tumor antigen peptide, an expression vector may alsocomprise a nucleic acid sequence coding for said MHC molecule. Thenucleic acid sequence coding for the MHC molecule may be present on thesame expression vector as the nucleic acid coding for the tumor antigenor the tumor antigen peptide, or both nucleic acids may be present ondifferent expression vectors. In the latter case, the two expressionvectors may be cotransfected into a cell. If a host cell expressesneither the tumor antigen or the tumor antigen peptide nor the MHCmolecule, both nucleic acids coding therefor may be transfected into thecell either on the same expression vector or on different expressionvectors. If the cell already expresses the MHC molecule, only thenucleic acid sequence coding for the tumor antigen or the tumor antigenpeptide can be transfected into the cell.

“Antisense molecules” or “antisense nucleic acids” may be used forregulating, in particular reducing, expression of a nucleic acid. Theterm “antisense molecule” or “antisense nucleic acid” refers accordingto the invention to an oligonucleotide which is an oligoribonucleotide,oligodeoxyribonucleotide, modified oligoribonucleotide or modifiedoligodeoxyribonucleotide and which hybridizes under physiologicalconditions to DNA comprising a particular gene or to mRNA of said gene,thereby inhibiting transcription of said gene and/or translation of saidmRNA. According to the invention, an “antisense molecule” also comprisesa construct which contains a nucleic acid or a part thereof in reverseorientation with respect to its natural promoter. An antisensetranscript of a nucleic acid or of a part thereof may form a duplex withnaturally occurring mRNA and thus prevent accumulation of or translationof the mRNA. Another possibility is the use of ribozymes forinactivating a nucleic acid.

In preferred embodiments, the antisense oligonucleotide hybridizes withan N-terminal or 5′ upstream site such as a translation initiation site,transcription initiation site or promoter site. In further embodiments,the antisense oligonucleotide hybridizes with a 3′ untranslated regionor mRNA splicing site.

In one embodiment, an oligonucleotide of the invention consists ofribonucleotides, deoxyribonucleotides or a combination thereof, with the5′ end of one nucleotide and the 3′ end of another nucleotide beinglinked to one another by a phosphodiester bond. These oligonucleotidesmay be synthesized in the conventional manner or produced recombinantly.

In preferred embodiments, an oligonucleotide of the invention is a“modified” oligonucleotide. Here, the oligonucleotide may be modified invery different ways, without impairing its ability to bind its target,in order to increase, for example, its stability or therapeuticefficacy. According to the invention, the term “modifiedoligonucleotide” means an oligonucleotide in which (i) at least two ofits nucleotides are linked to one another by a synthetic internucleosidebond (i.e. an internucleoside bond which is not a phosphodiester bond)and/or (ii) a chemical group which is usually not found in nucleic acidsis covalently linked to the oligonucleotide. Preferred syntheticinternucleoside bonds are phosphorothioates, alkyl phosphonates,phosphorodithioates, phosphate esters, alkyl phosphonothioates,phosphoramidates, carbamates, carbonates, phosphate triesters,acetamidates, carboxymethyl esters and peptides.

The term “modified oligonucleotide” also comprises oligonucleotideshaving a covalently modified base and/or sugar. “Modifiedoligonucleotides” comprise, for example, oligonucleotides with sugarresidues which are covalently bound to low molecular weight organicgroups other than a hydroxyl group at the 3′ position and a phosphategroup at the 5′ position. Modified oligonucleotides may comprise, forexample, a 2′-O-alkylated ribose residue or another sugar instead ofribose, such as arabinose.

It is to be understood that all embodiments described above with respectto oligonucleotides may also apply to polynucleotides.

By “small interfering RNA” or “siRNA” as used herein is meant anisolated RNA molecule, preferably greater than 10 nucleotides in length,more preferably greater than 15 nucleotides in length, and mostpreferably 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, or 30nucleotides in length that is used to identify a target gene or mRNA tobe degraded. A range of 19-25 nucleotides is the most preferred size forsiRNAs.

siRNA according to the invention can comprise partially purified RNA,substantially pure RNA, synthetic RNA, or recombinantly produced RNA, aswell as altered RNA that differs from naturally-occurring RNA by theaddition, deletion, substitution and/or alteration of one or morenucleotides. Such alterations can include addition of non-nucleotidematerial, such as to the end(s) of the siRNA or to one or more internalnucleotides of the siRNA; modifications that make the siRNA resistant tonuclease digestion (e.g., the use of 2′-substituted ribonucleotides ormodifications to the sugar-phosphate backbone); or the substitution ofone or more nucleotides in the siRNA with deoxyribonucleotides.Furthermore, siRNA may be modified to increase the stability thereof asdescribed above for modified oligonucleotides, in particular byintroducing one or more phosphorothioate linkages.

One or both strands of the siRNA can also comprise a 3′-overhang. Asused herein, a “3′-overhang” refers to at least one unpaired nucleotideextending from the 3′-end of an RNA strand. Thus in one embodiment, thesiRNA comprises at least one 3′-overhang of from 1 to about 6nucleotides (which includes ribonucleotides or deoxynucleotides) inlength, preferably from 1 to about 5 nucleotides in length, morepreferably from 1 to about 4 nucleotides in length, and particularlypreferably from about 2 to about 4 nucleotides in length. In theembodiment in which both strands of the siRNA molecule comprise a3′-overhang, the length of the overhangs can be the same or differentfor each strand. In a most preferred embodiment, the 3′-overhang ispresent on both strands of the siRNA, and is 2 nucleotides in length.For example, each strand of the siRNA of the invention can comprise3′-overhangs of dideoxythymidylic acid (“TT”) or diuridylic acid (“uu”).

In order to enhance the stability of the siRNA, the 3′-overhangs can bealso stabilized against degradation. In one embodiment, the overhangsare stabilized by including purine nucleotides, such as adenosine orguanosine nucleotides. Alternatively, substitution of pyrimidinenucleotides by modified analogues, e.g., substitution of uridinenucleotides in the 3′-overhangs with 2′-deoxythymidine, is tolerated anddoes not affect the efficiency of RNAi degradation. In particular, theabsence of a 2′-hydroxyl in the 2′-deoxythymidine significantly enhancesthe nuclease resistance of the 3′-overhang in tissue culture medium.

The sense and antisense strands of the siRNA can comprise twocomplementary, single-stranded RNA molecules or can comprise a singlemolecule in which two complementary portions are base-paired and arecovalently linked by a single-stranded “hairpin” area. That is, thesense region and antisense region can be covalently connected via alinker molecule. The linker molecule can be a polynucleotide ornon-nucleotide linker. Without wishing to be bound by any theory, it isbelieved that the hairpin area of the latter type of siRNA molecule iscleaved intracellularly by the “Dicer” protein (or its equivalent) toform a siRNA of two individual base-paired RNA molecules.

As used herein, “target mRNA” refers to an RNA molecule that is a targetfor downregulation.

siRNA can be expressed from pol III expression vectors without a changein targeting site, as expression of RNAs from pol III promoters is onlybelieved to be efficient when the first transcribed nucleotide is apurine.

siRNA according to the invention can be targeted to any stretch ofapproximately 19-25 contiguous nucleotides in any of the target mRNAsequences (the “target sequence”). Techniques for selecting targetsequences for siRNA are given, for example, in Tuschl T. et al., “ThesiRNA User Guide”, revised Oct. 11, 2002, the entire disclosure of whichis herein incorporated by reference. “The siRNA User Guide” is availableon the world wide web at a website maintained by Dr. Thomas Tuschl,Laboratory of RNA Molecular Biology, Rockefeller University, New York,USA, and can be found by accessing the website of the RockefellerUniversity and searching with the keyword “siRNA”. Thus, the sensestrand of the present siRNA comprises a nucleotide sequencesubstantially identical to any contiguous stretch of about 19 to about25 nucleotides in the target mRNA.

Generally, a target sequence on the target mRNA can be selected from agiven cDNA sequence corresponding to the target mRNA, preferablybeginning 50 to 100 nt downstream (i.e., in the 3′-direction) from thestart codon. The target sequence can, however, be located in the 5′- or3′-untranslated regions, or in the region nearby the start codon.

siRNA can be obtained using a number of techniques known to those ofskill in the art. For example, siRNA can be chemically synthesized orrecombinantly produced using methods known in the art, such as theDrosophila in vitro system described in U.S. published application2002/0086356 of Tuschl et al., the entire disclosure of which is hereinincorporated by reference.

Preferably, siRNA is chemically synthesized using appropriatelyprotected ribonucleoside phosphoramidites and a conventional DNA/RNAsynthesizer. siRNA can be synthesized as two separate, complementary RNAmolecules, or as a single RNA molecule with two complementary regions.

Alternatively, siRNA can also be expressed from recombinant circular orlinear DNA plasmids using any suitable promoter. Such embodiments areincluded according to the present invention when reference is madeherein to the administration of siRNA or the incorporation of siRNA intopharmaceutical compositions. Suitable promoters for expressing siRNA ofthe invention from a plasmid include, for example, the U6 or H1 RNA polIII promoter sequences and the cytomegalovirus promoter.

Selection of other suitable promoters is within the skill in the art.The recombinant plasmids of the invention can also comprise inducible orregulatable promoters for expression of the siRNA in a particular tissueor in a particular intracellular environment.

The siRNA expressed from recombinant plasmids can either be isolatedfrom cultured cell expression systems by standard techniques, or can beexpressed intracellularly. The use of recombinant plasmids to deliversiRNA to cells in vivo is discussed in more detail below. siRNA can beexpressed from a recombinant plasmid either as two separate,complementary RNA molecules, or as a single RNA molecule with twocomplementary regions.

Selection of plasmids suitable for expressing siRNA, methods forinserting nucleic acid sequences for expressing the siRNA into theplasmid, and methods of delivering the recombinant plasmid to the cellsof interest are within the skill in the art.

siRNA can also be expressed from recombinant viral vectorsintracellularly in vivo. The recombinant viral vectors comprisesequences encoding the siRNA and any suitable promoter for expressingthe siRNA sequences. The recombinant viral vectors can also compriseinducible or regulatable promoters for expression of the siRNA in aparticular tissue or in a particular intracellular environment. siRNAcan be expressed from a recombinant viral vector either as two separate,complementary RNA molecules, or as a single RNA molecule with twocomplementary regions.

The term “peptide” comprises oligo- and polypeptides and refers tosubstances comprising two or more, preferably 3 or more, preferably 4 ormore, preferably 6 or more, preferably 8 or more, preferably 10 or more,preferably 13 or more, preferably 16 more, preferably 21 or more and upto preferably 8, 10, 20, 30, 40 or 50, in particular 100 amino acidsjoined covalently by peptide bonds. The term “protein” refers to largepeptides, preferably to peptides with more than 100 amino acid residues,but in general the terms “peptides” and “proteins” are synonyms and areused interchangeably herein.

Preferably, the proteins and peptides described according to theinvention have been isolated. The terms “isolated protein” or “isolatedpeptide” mean that the protein or peptide has been separated from itsnatural environment. An isolated protein or peptide may be in anessentially purified state. The term “essentially purified” means thatthe protein or peptide is essentially free of other substances withwhich it is associated in nature or in vivo.

Such proteins and peptides may be used, for example, in producingantibodies and in an immunological or diagnostic assay or astherapeutics. Proteins and peptides described according to the inventionmay be isolated from biological samples such as tissue or cellhomogenates and may also be expressed recombinantly in a multiplicity ofpro- or eukaryotic expression systems.

For the purposes of the present invention, “variants” of a protein orpeptide or of an amino acid sequence comprise amino acid insertionvariants, amino acid deletion variants and/or amino acid substitutionvariants.

Amino acid insertion variants comprise amino- and/or carboxy-terminalfusions and also insertions of single or two or more amino acids in aparticular amino acid sequence. In the case of amino acid sequencevariants having an insertion, one or more amino acid residues areinserted into a particular site in an amino acid sequence, althoughrandom insertion with appropriate screening of the resulting product isalso possible.

Amino acid deletion variants are characterized by the removal of one ormore amino acids from the sequence.

Amino acid substitution variants are characterized by at least oneresidue in the sequence being removed and another residue being insertedin its place. Preference is given to the modifications being inpositions in the amino acid sequence which are not conserved betweenhomologous proteins or peptides and/or to replacing amino acids withother ones having similar properties.

Preferably, amino acid changes in protein variants are conservativeamino acid changes, i.e., substitutions of similarly charged oruncharged amino acids. A conservative amino acid change involvessubstitution of one of a family of amino acids which are related intheir side chains. Naturally occurring amino acids are generally dividedinto four families: acidic (aspartate, glutamate), basic (lysine,arginine, histidine), non-polar (alanine, valine, leucine, isoleucine,proline, phenylalanine, methionine, tryptophan), and uncharged polar(glycine, asparagine, glutamine, cystine, serine, threonine, tyrosine)amino acids. Phenylalanine, tryptophan, and tyrosine are sometimesclassified jointly as aromatic amino acids.

Preferably the degree of similarity, preferably identity between a givenamino acid sequence and an amino acid sequence which is a variant ofsaid given amino acid sequence will be at least 70%, preferably at least80%, preferably at least 85%, even more preferably at least 90% or mostpreferably at least 95%, 96%, 97%, 98% or 99%. The degree of similarityor identity is given preferably for a region of at least about 20, atleast about 40, at least about 60, at least about 80, at least about100, at least about 120, at least about 140, at least about 160, atleast about 200 or 250 amino acids. In preferred embodiments, the degreeof similarity or identity is given for the entire length of thereference amino acid sequence.

The peptides and amino acid variants described herein may be readilyprepared with the aid of known peptide synthesis techniques such as, forexample, by solid phase synthesis (Merrifield, 1964) and similar methodsor by recombinant DNA manipulation. The manipulation of DNA sequencesfor preparing proteins and peptides having substitutions, insertions ordeletions, is described in detail in Sambrook et al. (1989), forexample.

According to the invention, “derivatives” of proteins and peptides aremodified forms of proteins and peptides. Such modifications include anychemical modification and comprise single or multiple substitutions,deletions and/or additions of any molecules associated with the proteinor peptide, such as carbohydrates, lipids and/or proteins or peptides.The term “derivative” also extends to all functional chemicalequivalents of said proteins and peptides. Preferably, a modifiedpeptide has increased stability and/or increased immunogenicity.

According to the invention, a variant of a nucleic acid or amino acidsequence, a substantially corresponding amino acid sequence or afragment or derivative of a peptide preferably has a functional propertyof the nucleic acid or amino acid sequence, the amino acid sequence orthe peptide, respectively, from which it has been derived. Suchfunctional properties comprise the interaction with antibodies, theinteraction with other peptides or proteins, the selective binding ofnucleic acids and an enzymatic activity. In one embodiment, a variant ofa nucleic acid or amino acid sequence, a substantially correspondingamino acid sequence or a fragment or derivative of a peptide isimmunologically equivalent to the nucleic acid or amino acid sequence,the amino acid sequence or the peptide, respectively, from which it hasbeen derived. In one embodiment, the functional property is animmunological property. A particular property is the ability to form acomplex with MHC molecules and, where appropriate, generate an immuneresponse, preferably by stimulating cytotoxic or T helper cells. Afragment of a tumor antigen preferably comprises a sequence of at least6, in particular at least 8, at least 10, at least 12, at least 15, atleast 20, at least 30 or at least 50, consecutive amino acids of thetumor antigen. A fragment of a tumor antigen preferably comprises asequence of up to 8, in particular up to 10, up to 12, up to 15, up to20, up to 30 or up to 55, consecutive amino acids of the tumor antigen.A fragment of a tumor antigen is preferably a part of the tumor antigenwhich may be presented with MHC molecules and when so presented iscapable of stimulating a cellular response.

Preferred fragments of a tumor antigen are suitable for the stimulationof cytotoxic T-lymphocytes in vivo but also for the production ofexpanded and stimulated T-lymphocytes for the therapeutic adoptivetransfer ex vivo.

Antisera which contain specific antibodies specifically binding to thetarget protein can be prepared by various standard processes; see, forexample, “Monoclonal Antibodies: A Practical Approach” by PhilipShepherd, Christopher Dean ISBN 0-19-963722-9; “Antibodies: A LaboratoryManual” by Ed Harlow, David Lane, ISBN: 0879693142 and “UsingAntibodies: A Laboratory Manual: Portable Protocol NO” by Edward Harlow,David Lane, Ed Harlow ISBN 0879695447. Thereby it is also possible, togenerate affine and specific antibodies which recognize complex membraneproteins in their native form (Azorsa et al., J. Immunol. Methods 229:35-48, 1999; Anderson et al., J. Immunol. 143: 1899-1904, 1989;Gardsvoll, J. Immunol. Methods 234: 107-116, 2000). This is inparticular relevant for the preparation of antibodies which are to beused therapeutically, but also for many diagnostic applications. In thisrespect, it is possible to immunize with the whole protein, withextracellular partial sequences as well as with cells which express thetarget molecule in physiologically folded form.

Monoclonal antibodies are traditionally prepared using the hybridomatechnology. (for technical details see: “Monoclonal Antibodies: APractical Approach” by Philip Shepherd, Christopher Dean ISBN0-19-963722-9; “Antibodies: A Laboratory Manual” by Ed Harlow, DavidLane ISBN: 0879693142; “Using Antibodies: A Laboratory Manual: PortableProtocol NO” by Edward Harlow, David Lane, Ed Harlow ISBN: 0879695447).

It is known that only a small part of an antibody molecule, theparatope, is involved in binding of the antibody to its epitope (cf.Clark, W. R. (1986), The Experimental Foundations of Modern Immunology,Wiley & Sons, Inc., New York; Roitt, I. (1991), Essential Immunology,7th Edition, Blackwell Scientific Publications, Oxford). The pFc′ and Fcregions are, for example, effectors of the complement cascade but arenot involved in antigen binding. An antibody from which the pFc′ regionhas been enzymatically removed or which has been produced without thepFc′ region, referred to as F(ab′)₂ fragment, carries both antigenbinding sites of a complete antibody. Similarly, an antibody from whichthe Fc region has been enzymatically removed or which has been producedwithout said Fc region, referred to as Fab fragment, carries one antigenbinding site of an intact antibody molecule. Furthermore, Fab fragmentsconsist of a covalently bound light chain of an antibody and part of theheavy chain of said antibody, referred to as Fd. The Fd fragments arethe main determinants of antibody specificity (a single Fd fragment canbe associated with up to ten different light chains, without alteringthe specificity of the antibody) and Fd fragments, when isolated, retainthe ability to bind to an epitope.

Located within the antigen-binding part of an antibody arecomplementary-determining regions (CDRs) which interact directly withthe antigen epitope and framework regions (FRs) which maintain thetertiary structure of the paratope. Both the Fd fragment of the heavychain and the light chain of IgG immunoglobulins contain four frameworkregions (FR1 to FR4) which are separated in each case by threecomplementary-determining regions (CDR1 to CDR3). The CDRs and, inparticular, the CDR3 regions and, still more particularly, the CDR3region of the heavy chain are responsible to a large extent for antibodyspecificity.

Non-CDR regions of a mammalian antibody are known to be able to bereplaced by similar regions of antibodies with the same or a differentspecificity, with the specificity for the epitope of the originalantibody being retained. This made possible the development of“humanized” antibodies in which nonhuman CDRs are covalently linked tohuman FR and/or Fc/pFc′ regions to produce a functional antibody.

As another example, WO 92/04381 describes the production and use ofhumanized murine RSV antibodies in which at least part of the murine FRregions have been replaced with FR regions of a human origin. Antibodiesof this kind, including fragments of intact antibodies withantigen-binding capability, are often referred to as “chimeric”antibodies.

According to the invention, the term “antibody” also includes F(ab′)₂,Fab, Fv, and Fd fragments of antibodies, chimeric antibodies, in whichthe Fc and/or FR and/or CDR1 and/or CDR2 and/or light chain-CDR3 regionshave been replaced with homologous human or nonhuman sequences, chimericF(ab′)₂-fragment antibodies in which the FR and/or CDR1 and/or CDR2and/or light chain-CDR3 regions have been replaced with homologous humanor nonhuman sequences, chimeric Fab-fragment antibodies in which the FRand/or CDR1 and/or CDR2 and/or light chain-CDR3 regions have beenreplaced with homologous human or nonhuman sequences, and chimericFd-fragment antibodies in which the FR and/or CDR1 and/or CDR2 regionshave been replaced with homologous human or nonhuman sequences. The term“antibody” also comprises “single-chain” antibodies.

Non-antibody proteins and peptides which bind specifically to tumorantigens may replace antibodies when used according to the invention.Binding substances of this kind may be provided, for example, bydegenerate peptide libraries which may be prepared simply in solution inan immobilized form or as phage-display libraries. It is likewisepossible to prepare combinatorial libraries of peptides with one or moreamino acids. Libraries of peptoids and nonpeptidic synthetic residuesmay also be prepared.

Antibodies may also be coupled to a therapeutic label for displayingcells and tissues expressing tumor antigens. They may also be coupled totherapeutic effector moieties.

Detectable labels include any label that functions to: (i) provide adetectable signal; (ii) interact with a second label to modify thedetectable signal provided by the first or second label, e.g. FRET(Fluorescence Resonance Energy Transfer); (iii) affect mobility, e.g.electrophoretic mobility, by charge, hydrophobicity, shape, or otherphysical parameters, or (iv) provide a capture moiety, e.g., affinity,antibody/antigen, or ionic complexation. Suitable as label arestructures, such as fluorescent labels, luminescent labels, chromophorelabels, radioisotopic labels, isotopic labels, preferably stableisotopic labels, isobaric labels, enzyme labels, particle labels, inparticular metal particle labels, magnetic particle labels, polymerparticle labels, small organic molecules such as biotin, ligands ofreceptors or binding molecules such as cell adhesion proteins orlectins, label-sequences comprising nucleic acids and/or amino acidresidues which can be detected by use of binding agents, etc. Detectablelabels comprise, in a nonlimiting manner, barium sulfate, iocetamicacid, iopanoic acid, calcium ipodate, sodium diatrizoate, megluminediatrizoate, metrizamide, sodium tyropanoate and radio diagnostic,including positron emitters such as fluorine-18 and carbon-11, gammaemitters such as iodine-123, technetium-99m, iodine-131 and indium-111,nuclides for nuclear magnetic resonance, such as fluorine andgadolinium.

According to the invention, the term “therapeutic effector molecule”means any molecule which may exert a therapeutic effect. According tothe invention, a therapeutic effector molecule is preferably selectivelyguided to a cell which expresses one or more tumor antigens and includesanticancer agents, radioactive iodine-labeled compounds, toxins,cytostatic or cytolytic drugs, etc. Anticancer agents comprise, forexample, aminoglutethimide, azathioprine, bleomycin sulfate, busulfan,carmustine, chlorambucil, cisplatin, cyclophosphamide, cyclosporine,cytarabidine, dacarbazine, dactinomycin, daunorubin, doxorubicin, taxol,etoposide, fluorouracil, interferon-α, lomustine, mercaptopurine,methotrexate, mitotane, procarbazine HCl, thioguanine, vinblastinesulfate and vincristine sulfate. Other anticancer agents are described,for example, in Goodman and Gilman, “The Pharmacological Basis ofTherapeutics”, 8th Edition, 1990, McGraw-Hill, Inc., in particularChapter 52 (Antineoplastic Agents (Paul Calabresi and Bruce A. Chabner).Toxins may be proteins such as pokeweed antiviral protein, choleratoxin, pertussis toxin, ricin, gelonin, abrin, diphtheria exotoxin orPseudomonas exotoxin. Toxin residues may also be high energy-emittingradionuclides such as cobalt-60.

The term “major histocompatibility complex” or “MHC” includes MHC classI and class II and relates to a complex of genes present in allvertebrates. MHC proteins or molecules are involved in signaling betweenlymphocytes and antigen presenting cells in normal immune reactions bybinding peptides and presenting them for recognition by T cell receptors(TCR). MHC molecules bind peptides within an intracellular processingcompartment and present these peptides on the surface of antigenpresenting cells for recognition by T cells. The human MHC region alsotermed HLA is located on chromosome 6 and includes the class I and classII region. In one preferred embodiment of all aspects of the inventionan MHC molecule is an HLA molecule.

“Reduce” or “inhibit” as used herein means the ability to cause anoverall decrease, preferably of 20% or greater, more preferably of 50%or greater, and most preferably of 75% or greater, in the level, e.g. inthe level of protein or mRNA as compared to a reference sample (e.g., asample not treated with siRNA). This reduction or inhibition of RNA orprotein expression can occur through targeted mRNA cleavage ordegradation. Assays for protein expression or nucleic acid expressionare known in the art and include, for example, ELISA, western blotanalysis for protein expression, and northern blotting or RNaseprotection assays for RNA.

The term “patient” means according to the invention a human being, anonhuman primate or another animal, in particular a mammal such as acow, horse, pig, sheep, goat, dog, cat or a rodent such as a mouse andrat. In a particularly preferred embodiment, the patient is a humanbeing.

According to the invention the term “increased” or “increased amount”preferably refers to an increase by at least 10%, in particular at least20%, at least 50% or at least 100%. The amount of a substance is alsoincreased in a test sample such as a biological sample compared to areference sample if it is detectable in the test sample but absent ornot detectable in the reference sample.

According to the invention, the term “tumor” or “tumor disease” refersto a swelling or lesion formed by an abnormal growth of cells (calledneoplastic cells or tumor cells). By “tumor cell” is meant an abnormalcell that grows by a rapid, uncontrolled cellular proliferation andcontinues to grow after the stimuli that initiated the new growth cease.Tumors show partial or complete lack of structural organization andfunctional coordination with the normal tissue, and usually form adistinct mass of tissue, which may be either benign, pre-malignant ormalignant.

Preferably, a tumor disease according to the invention is a cancerdisease, i.e. a malignant disease and a tumor cell is a cancer cell.Preferably, a tumor disease is characterized by cells in which a tumornucleic acid and/or tumor antigen identified according to the inventionis expressed or abnormally expressed and a tumor cell or a circulatingor metastatic tumor cell is characterized by expression or abnormalexpression of a tumor nucleic acid and/or tumor antigen identifiedaccording to the invention. Preferably, a tumor disease, a tumor cell ora circulating or metastatic tumor cell is characterized by presentationof a tumor antigen identified according to the invention with class IMHC.

“Abnormal expression” means according to the invention that expressionis altered, preferably increased, compared to the state in a healthyindividual. An increase in expression refers to an increase by at least10%, in particular at least 20%, at least 50% or at least 100%. In oneembodiment, expression is only found in a diseases tissue, whileexpression in a healthy tissue is repressed.

Preferably, a tumor disease according to the invention is cancer,wherein the term “cancer” according to the invention comprisesleukemias, seminomas, melanomas, teratomas, lymphomas, neuroblastomas,gliomas, rectal cancer, endometrial cancer, kidney cancer, adrenalcancer, thyroid cancer, blood cancer, skin cancer, cancer of the brain,cervical cancer, intestinal cancer, liver cancer, colon cancer, stomachcancer, intestine cancer, head and neck cancer, gastrointestinal cancer,lymph node cancer, esophagus cancer, colorectal cancer, pancreas cancer,ear, nose and throat (ENT) cancer, breast cancer, prostate cancer,cancer of the uterus, ovarian cancer and lung cancer and the metastasesthereof. Examples thereof are lung carcinomas, mamma carcinomas,prostate carcinomas, colon carcinomas, renal cell carcinomas, cervicalcarcinomas, or metastases of the cancer types or tumors described above.The term cancer according to the invention also comprises cancermetastases.

Particularly preferred tumor diseases or cancers according to theinvention are selected from the group consisting of colorectal cancer,in particular colon cancer, gastric cancer, metastatic colorectalcancer, in particular metastatic colon cancer, and metastatic gastriccancer.

By “metastasis” is meant the spread of cancer cells from its originalsite to another part of the body. The formation of metastasis is a verycomplex process and depends on detachment of malignant cells from theprimary tumor, invasion of the extracellular matrix, penetration of theendothelial basement membranes to enter the body cavity and vessels, andthen, after being transported by the blood, infiltration of targetorgans. Finally, the growth of a new tumor, i.e. a secondary tumor ormetastatic tumor, at the target site depends on angiogenesis. Tumormetastasis often occurs even after the removal of the primary tumorbecause tumor cells or components may remain and develop metastaticpotential. In one embodiment, the term “metastasis” according to theinvention relates to “distant metastasis” which relates to a metastasiswhich is remote from the primary tumor and the regional lymph nodesystem.

The cells of a secondary or metastatic tumor are like those in theoriginal tumor. This means, for example, that, if colon cancermetastasizes to the liver, the secondary tumor is made up of abnormalcolon cells, not of abnormal liver cells. The tumor in the liver is thencalled metastatic colon cancer, not liver cancer. According to theinvention, metastatic colon cancer includes cancer in the lymph nodes,cancer in the liver, cancer in the lungs, cancer in the bones and cancerin the brain. Similarly, metastatic gastric cancer refers to cancer thathas spread from the stomach to distant and/or several sites in the bodyand includes cancer in the lymph nodes, cancer in the liver, cancer inthe lungs, cancer in the bones, cancer in the brain, cancer in theperitoneum and cancer in the rectum.

A relapse or recurrence occurs when a person is affected again by acondition that affected them in the past. For example, if a patient hassuffered from a tumor disease, has received a successful treatment ofsaid disease and again develops said disease said newly developeddisease may be considered as relapse or recurrence. However, accordingto the invention, a relapse or recurrence of a tumor disease may butdoes not necessarily occur at the site of the original tumor disease.Thus, for example, if a patient has suffered from colon tumor and hasreceived a successful treatment a relapse or recurrence may be theoccurrence of a colon tumor or the occurrence of a tumor at a sitedifferent to colon. A relapse or recurrence of a tumor also includessituations wherein a tumor occurs at a site different to the site of theoriginal tumor as well as at the site of the original tumor. Preferably,the original tumor for which the patient has received a treatment is aprimary tumor and the tumor at a site different to the site of theoriginal tumor is a secondary or metastatic tumor.

According to the invention, a biological sample may be a tissue sample,including bodily fluids, and/or a cellular sample and may be obtained inthe conventional manner such as by tissue biopsy, including punchbiopsy, and by taking blood, bronchial aspirate, sputum, urine, feces orother body fluids. According to the invention, the term “biologicalsample” also includes processed biological samples such as fractions orisolates of biological samples, e.g. nucleic acid and peptide/proteinisolates.

According to the invention, the term “immunoreactive cell” means a cellwhich can mature into an immune cell (such as B cell, T helper cell, orcytolytic T cell) with suitable stimulation. Immunoreactive cellscomprise CD34⁺ hematopoietic stem cells, immature and mature T cells andimmature and mature B cells. If production of cytolytic or T helpercells recognizing a tumor antigen is desired, the immunoreactive cell iscontacted with a cell expressing a tumor antigen under conditions whichfavor production, differentiation and/or selection of cytolytic T cellsand of T helper cells. The differentiation of T cell precursors into acytolytic T cell, when exposed to an antigen, is similar to clonalselection of the immune system.

The terms “T cell” and “T lymphocyte” are used interchangeably hereinand include T helper cells (CD4+ T cells) and cytotoxic T cells (CTLs,CD8+ T cells) which comprise cytolytic T cells.

Some therapeutic methods are based on a reaction of the immune system ofa patient, which results in a lysis of diseases cells such as cancercells which present a tumor antigen with class I MHC. In thisconnection, for example autologous cytotoxic T lymphocytes specific fora complex of a tumor antigen peptide and an MHC molecule may beadministered to a patient having a tumor disease. The production of suchcytotoxic T lymphocytes in vitro is known. An example of a method ofdifferentiating T cells can be found in WO-A-9633265. Generally, asample containing cells such as blood cells is taken from the patientand the cells are contacted with a cell which presents the complex andwhich can cause propagation of cytotoxic T lymphocytes (e.g. dendriticcells). The target cell may be a transfected cell such as a COS cell.These transfected cells present the desired complex on their surfaceand, when contacted with cytotoxic T lymphocytes, stimulate propagationof the latter. The clonally expanded autologous cytotoxic T lymphocytesare then administered to the patient.

In another method of selecting cytotoxic T lymphocytes, fluorogenictetramers of MHC class I molecule/peptide complexes are used forobtaining specific clones of cytotoxic T lymphocytes (Altman et al.,Science 274:94-96, 1996; Dunbar et al., Curr. Biol. 8:413-416, 1998).

Furthermore, cells presenting the desired complex (e.g. dendritic cells)may be combined with cytotoxic T lymphocytes of healthy individuals oranother species (e.g. mouse) which may result in propagation of specificcytotoxic T lymphocytes with high affinity. The high affinity T cellreceptor of these propagated specific T lymphocytes may be cloned andoptionally humanized to a different extent, and the T cell receptorsthus obtained then transduced via gene transfer, for example usingretroviral vectors, into T cells of patients. Adoptive transfer may thenbe carried out using these genetically altered T lymphocytes(Stanislawski et al., Nat. Immunol. 2:962-70, 2001; Kessels et al., Nat.Immunol. 2:957-61, 2001).

Cytotoxic T lymphocytes may also be generated in vivo in a manner knownper se. One method uses nonproliferative cells expressing an MHC classI/peptide complex. The cells used here will be those which usuallyexpress the complex, such as irradiated tumor cells or cells transfectedwith one or both genes necessary for presentation of the complex (i.e.the antigenic peptide and the presenting MHC molecule). Anotherpreferred form is the introduction of the tumor antigen in the form ofrecombinant RNA which may be introduced into cells by liposomal transferor by electroporation, for example. The resulting cells present thecomplex of interest and are recognized by autologous cytotoxic Tlymphocytes which then propagate.

A similar effect can be achieved by combining a tumor antigen or a tumorantigen peptide with an adjuvant in order to make incorporation intoantigen-presenting cells in vivo possible. The tumor antigen or tumorantigen peptide may be represented as protein, as DNA (e.g. within avector) or as RNA. The tumor antigen may be processed to produce apeptide partner for the MHC molecule, while a fragment thereof may bepresented without the need for further processing. The latter is thecase in particular, if these can bind to MHC molecules. Preference isgiven to administration forms in which the complete antigen is processedin vivo by a dendritic cell, since this may also produce T helper cellresponses which are needed for an effective immune response (Ossendorpet al., Immunol Lett. 74:75-9, 2000; Ossendorp et al., J. Exp. Med.187:693-702, 1998). In general, it is possible to administer aneffective amount of the tumor antigen to a patient by intradermalinjection, for example. However, injection may also be carried outintranodally into a lymph node (Maloy et al., Proc Natl Acad Sci USA98:3299-303, 2001).

The pharmaceutical compositions and methods of treatment describedaccording to the invention may also be used for immunization orvaccination to therapeutically treat or prevent a disease describedherein. According to the invention, the terms “immunization” or“vaccination” preferably relate to an increase in or activation of animmune response to an antigen. It is possible to use animal models fortesting an immunizing effect on cancer. For example, human cancer cellsmay be introduced into a mouse to generate a tumor. The effect on thecancer cells (for example reduction in tumor size) may be measured as ameasure for the effectiveness of an immunization by an agentadministered to the animal.

As part of the composition for an immunization or a vaccination,preferably one or more agents as described herein are administeredtogether with one or more adjuvants for inducing an immune response orfor increasing an immune response. An adjuvant is a substance whichenhances an immune response. Adjuvants may enhance the immune responseby providing an antigen reservoir (extracellularly or in macrophages),activating macrophages and/or stimulating particular lymphocytes.Adjuvants are known and comprise in a nonlimiting way monophosphoryllipid A (MPL, SmithKline Beecham), saponins such as QS21 (SmithKlineBeecham), DQS21 (SmithKline Beecham; WO 96/33739), QS7, QS17, QS18 andQS-L1 (So et al., Mol. Cells. 7:178-186, 1997), incomplete Freund'sadjuvant, complete Freund's adjuvant, vitamin E, montanide, alum, CpGoligonucleotides (cf. Kreig et al., Nature 374:546-9, 1995) and variouswater-in-oil emulsions prepared from biologically degradable oils suchas squalene and/or tocopherol. Preferably, according to the invention,peptides are administered in a mixture with DQS21/MPL. The ratio ofDQS21 to MPL is typically about 1:10 to 10:1, preferably about 1:5 to5:1 and in particular about 1:1. For administration to humans, a vaccineformulation typically contains DQS21 and MPL in a range from about 1 μgto about 100 μg.

Other substances which stimulate an immune response of the patient mayalso be administered. It is possible, for example, to use cytokines in avaccination, owing to their regulatory properties on lymphocytes. Suchcytokines comprise, for example, interleukin-12 (IL-12) which was shownto increase the protective actions of vaccines (cf. Science268:1432-1434, 1995), GM-CSF and IL-18.

There are a number of compounds which enhance an immune response andwhich therefore may be used in a vaccination. Said compounds comprisecostimulating molecules provided in the form of proteins or nucleicacids such as B7-1 and B7-2 (CD80 and CD86, respectively).

Peptides may be administered in a manner known per se. In oneembodiment, nucleic acids are administered by ex vivo methods, i.e. byremoving cells from a patient, genetic modification of said cells inorder to incorporate a nucleic acid and reintroduction of the alteredcells into the patient. This generally comprises introducing afunctional copy of a gene into the cells of a patient in vitro andreintroducing the genetically altered cells into the patient. Thefunctional copy of the gene is under the functional control ofregulatory elements which allow the gene to be expressed in thegenetically altered cells. Transfection and transduction methods areknown to the skilled worker.

The invention also provides for administering nucleic acids in vivo byusing, for example, vectors such as viruses and target-controlledliposomes.

In a preferred embodiment, a virus or viral vector for administering anucleic acid is selected from the group consisting of adenoviruses,adeno-associated viruses, pox viruses, including vaccinia virus andattenuated pox viruses, Semliki Forest virus, retroviruses, Sindbisvirus and Ty virus-like particles. Particular preference is given toadenoviruses and retroviruses. The retroviruses are typicallyreplication-deficient (i.e. they are incapable of generating infectiousparticles).

Methods of introducing nucleic acids into cells in vitro or in vivocomprise transfection of nucleic acid calcium phosphate precipitates,transfection of nucleic acids associated with DEAE, transfection orinfection with the above viruses carrying the nucleic acids of interest,liposome-mediated transfection, and the like. In particular embodiments,preference is given to directing the nucleic acid to particular cells.In such embodiments, a carrier used for administering a nucleic acid toa cell (e.g. a retrovirus or a liposome) may have a bound target controlmolecule. For example, a molecule such as an antibody specific for asurface membrane protein on the target cell or a ligand for a receptoron the target cell may be incorporated into or attached to the nucleicacid carrier. Preferred antibodies comprise antibodies which bindselectively a tumor antigen. If administration of a nucleic acid vialiposomes is desired, proteins binding to a surface membrane proteinassociated with endocytosis may be incorporated into the liposomeformulation in order to make target control and/or uptake possible. Suchproteins comprise capsid proteins or fragments thereof which arespecific for a particular cell type, antibodies to proteins which areinternalized, proteins addressing an intracellular site, and the like.

The therapeutically active compounds of the invention may beadministered via any conventional route, including by injection orinfusion. The administration may be carried out, for example, orally,intravenously, intraperitonealy, intramuscularly, subcutaneously ortransdermally. Preferably, antibodies are therapeutically administeredby way of a lung aerosol. Antisense nucleic acids are preferablyadministered by slow intravenous administration.

The compositions of the invention are administered in effective amounts.An “effective amount” refers to the amount which achieves a desiredreaction or a desired effect alone or together with further doses. Inthe case of treatment of a particular disease or of a particularcondition, the desired reaction preferably relates to inhibition of thecourse of the disease. This comprises slowing down the progress of thedisease and, in particular, interrupting or reversing the progress ofthe disease. The desired reaction in a treatment of a disease or of acondition may also be delay of the onset or a prevention of the onset ofsaid disease or said condition. According to the invention, a diagnosisor treatment of cancer may also include the diagnosis or treatment ofcancer metastases which have already formed or will form. According tothe invention, the term “treatment” comprises therapeutic andprophylactic treatment, i.e. prevention.

An effective amount of a composition of the invention will depend on thecondition to be treated, the severeness of the disease, the individualparameters of the patient, including age, physiological condition, sizeand weight, the duration of treatment, the type of an accompanyingtherapy (if present), the specific route of administration and similarfactors. Accordingly, the doses of the compositions of the inventionadministered may depend on various of such parameters. In the case thata reaction in a patient is insufficient with an initial dose, higherdoses (or effectively higher doses achieved by a different, morelocalized route of administration) may be used.

The pharmaceutical compositions of the invention are preferably sterileand contain an effective amount of the therapeutically active substanceto generate the desired reaction or the desired effect.

Generally, doses of a peptide of from 1 ng to 1 mg, preferably from 10ng to 100 n, are formulated and administered. If the administration ofnucleic acids (DNA and RNA) is desired, doses of from 1 ng to 0.1 mg maybe formulated and administered.

The pharmaceutical compositions of the invention are generallyadministered in pharmaceutically compatible amounts and inpharmaceutically compatible preparation. The term “pharmaceuticallycompatible” refers to a nontoxic material which does not interact withthe action of the active component of the pharmaceutical composition.Preparations of this kind may usually contain salts, buffer substances,preservatives, carriers, supplementing immunity-enhancing substancessuch as adjuvants, e.g. CpG oligonucleotides, cytokines, chemokines,saponin, GM-CSF and/or RNA and, where appropriate, other therapeuticallyactive compounds. When used in medicine, the salts should bepharmaceutically compatible. However, salts which are notpharmaceutically compatible may used for preparing pharmaceuticallycompatible salts and are included in the invention. Pharmacologicallyand pharmaceutically compatible salts of this kind comprise in anonlimiting way those prepared from the following acids: hydrochloric,hydrobromic, sulfuric, nitric, phosphoric, maleic, acetic, salicylic,citric, formic, malonic, succinic acids, and the like. Pharmaceuticallycompatible salts may also be prepared as alkali metal salts or alkalineearth metal salts, such as sodium salts, potassium salts or calciumsalts.

A pharmaceutical composition of the invention may comprise apharmaceutically compatible carrier. The term “carrier” refers to anorganic or inorganic component, of a natural or synthetic nature, inwhich the active component is combined in order to facilitateapplication. According to the invention, the term “pharmaceuticallycompatible carrier” includes one or more compatible solid or liquidfillers, diluents or encapsulating substances, which are suitable foradministration to a patient. The components of the pharmaceuticalcomposition of the invention are usually such that no interaction occurswhich substantially impairs the desired pharmaceutical efficacy.

The pharmaceutical compositions of the invention may contain suitablebuffer substances such as acetic acid in a salt, citric acid in a salt,boric acid in a salt and phosphoric acid in a salt.

The pharmaceutical compositions may, where appropriate, also containsuitable preservatives such as benzalkonium chloride, chlorobutanol,paraben and thimerosal.

The pharmaceutical compositions are usually provided in a uniform dosageform and may be prepared in a manner known per se. Pharmaceuticalcompositions of the invention may be in the form of capsules, tablets,lozenges, solutions, suspensions, syrups, elixirs or in the form of anemulsion, for example.

Compositions suitable for parenteral administration usually comprise asterile aqueous or nonaqueous preparation of the active compound, whichis preferably isotonic to the blood of the recipient. Examples ofcompatible carriers and solvents are Ringer solution and isotonic sodiumchloride solution. In addition, usually sterile, fixed oils are used assolution or suspension medium.

It should be emphasized that the term “comprises/comprising” when usedin this specification is taken to specify the presence of statedfeatures, integers, steps or components but does not preclude thepresence or addition of one or more other features, integers, steps,components or groups thereof. The mere fact that certain measures arerecited in mutually different dependent claims or described in differentembodiments does not indicate that a combination of these measurescannot be used to advantage. However, the term “comprises/comprising”also includes embodiments consisting of stated features, integers, stepsor components.

The present invention is described in detail by the figures and examplesbelow, which are used only for illustration purposes and are not meantto be limiting. Owing to the description and the examples, furtherembodiments which are likewise included in the invention are accessibleto the skilled worker.

FIGURES

FIG. 1. The nucleic acid according to SEQ ID NO: 1 is expressed innormal and cancerous colonic and gastric tissue and encodes a plasmamembrane protein which is present in epithelial cells of such tissues.A) Endpoint 35 cycle RT-PCR in normal tissues and colon cancer. B)Quantitative 40 cycle real-time RT-PCR in normal tissues. C)Quantitative 40 cycle real-time RT-PCR in colon cancer and gastriccancer. For each normal tissue the mean expression values of twoindividual tissue specimens are shown. Error bars, STD; dashed line,expression cut-off D) IF microscopic analysis of CHO cells transfectedwith SEQ ID NO: 2-fluorescent marker and stained with anti-SEQ ID NO: 2polyclonal antibody. E) IHC detection of the expression of the proteinaccording to SEQ ID NO: 2 in normal colon and colon cancer.

FIG. 2. The protein according to SEQ ID NO: 2 is a plasma membraneprotein. Predicted plasma membrane topology and structural features ofthe protein according to SEQ ID NO: 2.

EXAMPLES

The techniques and methods used herein are described herein or carriedout in a manner known per se and as described, for example, in Sambrooket al., Molecular Cloning: A Laboratory Manual, 2nd Edition (1989) ColdSpring Harbor Laboratory Press, Cold Spring Harbor, N.Y. All methodsincluding the use of kits and reagents are carried out according to themanufacturers' information unless specifically indicated.

Example 1 Material and Methods Data Mining Strategy

As a first step, we created a general human expressed sequence tag (EST)file from all available libraries that contained the keyword “Homosapiens” in the organism field of the dbEST report file(ftp://ncbi.nlm.nih.gov/repository/dbEST). To reduce complexity of theapproach only libraries representing more than 100 ESTs and only ESTsencoding known full length genes were considered. Next, acolon/intestine tissue specific subfile was generated by extracting allthose ESTs from the general file that contained the words “colon” and“intestine” in the library name, organism, tissue type, organ, or cellline field. To account for the fact, that several EST may be derivedfrom the same gene, the colon/intestine tissue ESTs were grouped intoclusters assembling ESTs that shared one or more stretches of highsequence identity. The sequence homology searching program blastn(www.ncbi.nlm.nih.gov/BLAST) was run sequentially with the homologystringency set at S=300; V=300; B=300; n=−20 for each sequence recordedin the colon/intestine tissue EST subfile against all of the human ESTsin the general list. For each query EST from the colon/intestine tissuesubfile, the search extracted a list of EST entries (hits) from thegeneral EST file, each of them annotated with its tissue origin,providing an “electronic Northern”. Determination of the number ofdifferent non-colon/intestine tissues represented in such a hit list wasused as a measure for the extent of colon/intestine tissue specificityof each individual EST. All candidates obtained by this procedure weresubjected to motif and structure analysis by SMART(http://smart.embl.de/smart) to identify potential surface molecules(minimal requirements: at least one hydrophobic region qualifying astransmembrane domains according to TMHMM transmembrane prediction server(www.cbs.dtu.dk/services/TMHMM-2.0), and prediction of at least oneextracellular domain).

RNA-Isolation, RT-PCR and Real-Time RT-PCR

RNA extraction, first-strand cDNA synthesis, RT-PCR and quantitativereal-time RT-PCR were performed as previously described (Koslowski etal., Cancer Res. 64: 5988-93, 2004). Briefly, total cellular RNA wasextracted from frozen tissue specimens using RNeasy Mini Kit (Qiagen),primed with a dT18 oligonucleotide and reverse transcribed withSuperscript II (Invitrogen) according to the manufacturer'sinstructions. Integrity of the obtained cDNA was tested by amplificationof p53 transcripts in a 30-cycle PCR (sense, 5′-CGT GAG CGC TTC GAG ATGTTC CG-3′ (SEQ ID NO: 4); antisense, 5′-CCT AAC CAG CTG CCC AAC TGTAG-3′ (SEQ ID NO: 5); annealing temperature 67° C.).

For end-point analysis SEQ ID NO: 1-specific oligonucleotides (sense5′-ACT CTG CCT GTC CTC AGG CTG-3′ (SEQ ID NO: 6); antisense 5′-GTG CTTTCT TCT CCA GTC CAG-3′ (SEQ ID NO: 7), 60° C. annealing) were used in a35 cycle RT-PCR. Real-time quantitative expression analysis wasperformed in triplicates in a 40 cycle RT-PCR. After normalization toHPRT (sense 5′-TGA CAC TGG CAA AAC AAT GCA-3′ (SEQ ID NO: 8); antisense5′-GGT CCT TTT CAC CAG CAA GCT-3′ (SEQ ID NO: 9, 62° C. annealing)target transcripts in tumor samples were quantified relative to normaltissues using ΔΔCT calculation. Specificity of PCR reactions wasconfirmed by cloning and sequencing of amplification products fromarbitrarily selected samples.

Antisera, Immunofluorescence and Immunochemistry

The polyclonal antiserum was raised against a KLH-coupled syntheticpeptide (SEQ ID NO: 3) covering aa 120-132 of SEQ ID NO: 2 andaffinity-purified by a custom antibody service (Charles River).Immunohistochemistry was performed on paraffin-embedded tissue sectionsusing the VECTOR NovaRED Substrate Kit (Vector) according to themanufacturer's instructions.

Example 2 Screening for Colon Epithelial Cell Specific Targets

A genome-wide data mining strategy was applied to search for targets formonoclonal antibody therapy of colon cancer. The approach was based ondigital cDNA library subtraction to discover differentiation genes withspecificity for colonic epithelial cells with at least one hydrophobicregion qualifying as transmembrane domain. Such candidates weresubsequently tested for conserved expression in cancers derived fromthis cell lineage. One of the hits of the computational screen complyingwith the search criteria was the sequence according to SEQ ID NO: 1.

To experimentally validate the in silico predicted colon-specificexpression of said sequence, we initially tested a small set of normaltissues and colon cancer samples by specific 35 cycle endpoint RT-PCR(FIG. 1A). Expression of the sequence was not detected in any normaltissue except colon and was maintained in 5/7 colon cancer samples.Next, a more comprehensive and sensitive expression analysis of thesequence in a set of 23 different normal human tissues was performed byquantitative 40 cycle real-time RT-PCR (FIG. 1B). Again, the sequencewas found to be highly expressed in normal colon. In addition to theendpoint RT-PCR results, expression was also detected in stomach, albeitat levels 100-fold lower than in colon. In all other normal tissues notranscripts or only trace amounts of transcripts could be detected. Alltissues not exceeding the expression cut-off (mean expression in allnormal non-colonic and non-gastric tissue samples +3 standard deviations(99% percentile)) were classified as negative (Tab. 1).

TABLE 1 Expression of SEQ ID NO: 1 in tissues typed by quantitativereal- time RT-PCR. Specimens obtained from two to five differentindividuals were investigated per normal tissue type. Cut-off for normaltissues was set to mean expression in normal tissues except colon andstomach +3 standard deviations. In tumor tissues only expression valuesat least 10 fold above expression cut-off in normal tissues were scoredpositive. Positive/tested Normal tissues Colon 5/5 Stomach 3/3 Brain 0/2Placenta 0/2 Liver 0/2 Pancreas 0/2 rest. PBMCs 0/2 prolif. PBMCs 0/2Lung 0/2 Breast 0/2 Ovary 0/2 Kidney 0/2 Testis 0/2 Spleen 0/2 Lymphnode 0/2 Endometrium 0/2 Esophagus 0/2 Skin 0/2 Thymus 0/2 Bladder 0/2Muscle 0/2 Prostate 0/2 Cervix 0/2 Cancerous tissues Colon cancer 17/20Gastric cancer  9/15

Profiling of tumor specimens revealed that 17/20 (85%) colon cancers and9/15 (60%) gastric cancers expressed the sequence (FIG. 1 c). In ordernot to overestimate expression frequency as measured by real-time RT-PCRin cancer samples, only transcript levels of at least 10-fold abovenormal tissue expression cut-off were classified as positive.

For analysis of the protein encoded by the sequence according to SEQ IDNO: 1 (SEQ ID NO: 2), we raised a polyclonal rabbit antibody against apeptide epitope specific for said amino acid sequence (aa 120-132) (SEQID NO: 3). Specificity of the antibody was experimentally confirmed byimmunofluorescence staining of CHO cells transfected with a C-terminallyfluorescent marker-tagged construct of SEQ ID NO: 2 (FIG. 1D). Anti-SEQID NO: 2 showed distinct staining of the SEQ ID NO: 2-fluorescent markerfusion protein at the plasma membrane of transfected cells and was notreactive in non-transfected control cells. Immunohistochemistry withanti-SEQ ID NO: 2 antibody on sections from normal colon tissue revealeda clear and specific membrane staining of the epithelial cells in thecolonic mucosa (FIG. 1E), no staining was observed in adjacent stromaland non-epithelial cells. In colon cancer sections we found specific andhomogenous staining of the neoplastic cell population. Though additionalcytoplasmic immunostaining was observed, staining of tumor cells wasclearly accentuated at the plasma membrane, substantiating theimmunofluorescence results that SEQ ID NO: 2 is a cell surface protein.

The predicted overall structure and membrane topology of SEQ ID NO: 2perfectly resembles that of a protein expressed on the surface ofepithelial cells which is incorporated as an integral protein into themembrane (FIG. 2). A cleavable signal peptide is followed by twoimmunoglobulin (Ig) folds in the large extracellular region, a largervariable (V)-like domain and a smaller constant (C)-like domain. Thesingle transmembrane domain is followed by the cytoplasmic B30.2 domainwhich is composed of PRY and SPRY subdomains. It was shown that SPRYdomains are evolutionary ancient, whereas B30.2 domains are a morerecent evolutionary adaption, comprising the combination of SPRY with aPRY domain. B30.2 domains occur in a variety of cellular proteins withvarious functions and mediate protein-protein interactions.

1. A pharmaceutical composition comprising an inhibitor of expressionand/or activity of a tumor antigen, wherein said tumor antigen comprisesan amino acid sequence encoded by a nucleic acid which comprises thenucleic acid sequence according to SEQ ID NO: 1 of the sequence listingor a variant of said nucleic acid sequence.
 2. The pharmaceuticalcomposition as claimed in claim 1, wherein (i) the inhibitor ofexpression of a tumor antigen is an inhibitory nucleic acid selectivelyhybridizing to the nucleic acid which comprises the nucleic acidsequence according to SEQ ID NO: 1 of the sequence listing or a variantof said nucleic acid sequence, the inhibitory nucleic acid preferablybeing selected from the group consisting of an anti-senseoligonucleotide, a ribozyme, iRNA, siRNA or a DNA encoding the same or(ii) the inhibitor of activity of a tumor antigen is an antibodyspecifically binding to said tumor antigen.
 3. A pharmaceuticalcomposition comprising a ligand of a tumor antigen or a ligand of anucleic acid encoding a tumor antigen, wherein said tumor antigencomprises an amino acid sequence encoded by a nucleic acid whichcomprises the nucleic acid sequence according to SEQ ID NO: 1 of thesequence listing or a variant of said nucleic acid sequence, and whereinsaid ligand of a tumor antigen or ligand of a nucleic acid encoding atumor antigen is attached to one or more therapeutic effector moieties,said therapeutic effector molecule preferably being a radiolabel,cytotoxin or cytotoxic enzyme.
 4. The pharmaceutical composition asclaimed in claim 3, wherein the ligand of a tumor antigen comprises anantibody specifically binding to said tumor antigen or the ligand of anucleic acid encoding a tumor antigen is a nucleic acid selectivelyhybridizing to said nucleic acid.
 5. A pharmaceutical compositioncomprising one or more agents selected from the group consisting of: (i)a peptide comprising the amino acid sequence of a tumor antigen or of atumor antigen peptide derived from said tumor antigen, or a derivativeof said peptide, (ii) a nucleic acid which codes for a peptidecomprising the amino acid sequence of a tumor antigen or of a tumorantigen peptide derived from said tumor antigen, or a derivative of saidnucleic acid, (iii) a host cell which codes for a peptide comprising theamino acid sequence of a tumor antigen or of a tumor antigen peptidederived from said tumor antigen, (iv) a virus which codes for a peptidecomprising the amino acid sequence of a tumor antigen or of a tumorantigen peptide derived from said tumor antigen, (v) a cell presenting apeptide comprising the amino acid sequence of a tumor antigen peptidederived from a tumor antigen, or a derivative of said peptide, (vi) anantibody or T cell receptor which binds to a peptide comprising theamino acid sequence of a tumor antigen or of a tumor antigen peptidederived from said tumor antigen, (vii) an immunoreactive cell sensitizedin vitro to recognize a peptide comprising the amino acid sequence of atumor antigen or of a tumor antigen peptide derived from said tumorantigen, and (viii) an effector cell or stem cell transduced with anucleic acid encoding a T cell receptor that recognizes a peptidecomprising the amino acid sequence of a tumor antigen or of a tumorantigen peptide derived from said tumor antigen, wherein said tumorantigen comprises an amino acid sequence encoded by a nucleic acid whichcomprises the nucleic acid sequence according to SEQ ID NO: 1 of thesequence listing or a variant of said nucleic acid sequence and saidtumor antigen peptide comprises an amino acid sequence substantiallycorresponding to the amino acid sequence of a fragment of said tumorantigen.
 6. The pharmaceutical composition as claimed in claim 5,wherein the peptide is a MHC class I or class II presented peptide orcan be processed to produce an MHC class I or class II presentedpeptide.
 7. The pharmaceutical composition as claimed in claim 5,wherein the host cell expresses an MHC molecule which binds to theencoded peptide or a procession product thereof.
 8. The pharmaceuticalcomposition as claimed in claim 5, wherein the antibody is a monoclonal,chimeric, human or humanized antibody, or is a fragment of an antibodyor a synthetic antibody.
 9. The pharmaceutical composition as claimed inclaim 5 which is in the form of a therapeutic or prophylactic tumorvaccine.
 10. The pharmaceutical composition as claimed in claim 5 foruse in treating or preventing a tumor disease.
 11. A method of treatinga patient having a tumor disease or being at risk of developing a tumordisease comprising administering a pharmaceutical composition as claimedin any of claim 1, 3, or 5 to the patient, said administering preferablyinducing or promoting CTL activity against a tumor characterized bypresentation of a tumor antigen comprising an amino acid sequenceencoded by a nucleic acid which comprises the nucleic acid sequenceaccording to SEQ ID NO: 1 of the sequence listing or a variant of saidnucleic acid sequence with class I MHC.
 12. A method for diagnosis,detection or monitoring of a tumor disease comprising the detection ofand/or determination of the quantity of one or more parameters selectedfrom the group consisting of: (i) a nucleic acid which codes for apeptide comprising the amino acid sequence of a tumor antigen, (ii) apeptide comprising the amino acid sequence of a tumor antigen or of atumor antigen peptide derived from said tumor antigen, (iii) an antibodywhich binds to a peptide comprising the amino acid sequence of a tumorantigen or of a tumor antigen peptide derived from said tumor antigen,(iv) a T cell that recognizes a peptide comprising the amino acidsequence of a tumor antigen or of a tumor antigen peptide derived fromsaid tumor antigen and/or (v) a cell which presents a peptide comprisingthe amino acid sequence of a tumor antigen peptide derived from a tumorantigen, in a biological sample isolated from a patient, wherein saidtumor antigen comprises an amino acid sequence encoded by a nucleic acidwhich comprises the nucleic acid sequence according to SEQ ID NO: 1 ofthe sequence listing or a variant of said nucleic acid sequence and saidtumor antigen peptide comprises an amino acid sequence substantiallycorresponding to the amino acid sequence of a fragment of said tumorantigen.
 13. A method for detecting circulating tumor cells in a patientcomprising the detection of and/or determination of the quantity of (i)a nucleic acid which codes for a peptide comprising the amino acidsequence of a tumor antigen, and/or (ii) a peptide comprising the aminoacid sequence of a tumor antigen or of a tumor antigen peptide derivedfrom said tumor antigen, in a biological sample containing or suspectedof containing disseminating or circulating tumor cells or metastatictumor cells isolated from said patient, wherein said tumor antigencomprises an amino acid sequence encoded by a nucleic acid whichcomprises the nucleic acid sequence according to SEQ ID NO: 1 of thesequence listing or a variant of said nucleic acid sequence and saidtumor antigen peptide comprises an amino acid sequence substantiallycorresponding to the amino acid sequence of a fragment of said tumorantigen.
 14. A method of detecting metastatic colon cancer cells ormetastatic gastric cancer cells in a patient comprising the detection ofand/or determination of the quantity of (i) a nucleic acid which codesfor a peptide comprising the amino acid sequence of a tumor antigen,and/or (ii) a peptide comprising the amino acid sequence of a tumorantigen or of a tumor antigen peptide derived from said tumor antigen,in a biological sample isolated from a tissue or organ of said patienthaving a tumor wherein the cells when the tissue or organ is free oftumors do not substantially express said nucleic acid or peptide,wherein said tumor antigen comprises an amino acid sequence encoded by anucleic acid which comprises the nucleic acid sequence according to SEQID NO: 1 of the sequence listing or a variant of said nucleic acidsequence and said tumor antigen peptide comprises an amino acid sequencesubstantially corresponding to the amino acid sequence of a fragment ofsaid tumor antigen.
 15. The method as claimed in any of claims 12 to 14,wherein the biological sample is from a tissue or organ wherein thecells when the tissue or organ is free of tumors do not substantiallyexpress said tumor antigen and/or a nucleic acid encoding said tumorantigen.
 16. The method as claimed in any of claims 12 to 14, whereinthe detection and/or determination of the quantity comprises: (i)contacting the biological sample with an agent which binds specificallyto the nucleic acid, the peptide, the antibody, the T cell or the cellwhich is to be detected and/or the quantity of which is to bedetermined, and (ii) detecting the formation of and/or determining thequantity of a complex between the agent and the nucleic acid, thepeptide, the antibody, the T cell or the cell which is to be detected orthe quantity of which is to be determined.
 17. The method as claimed inclaim 16, wherein (i) the agent which binds specifically to the nucleicacid comprises an oligonucleotide, which hybridizes specifically to saidnucleic acid, (ii) the agent which binds specifically to the peptidecomprises an antibody binding specifically to said peptide, (iii) theagent which binds specifically to the antibody comprises a peptidebinding specifically to said antibody, or (iv) the agent which bindsspecifically to the T cell comprises a cell presenting a complex betweenan MHC molecule and the peptide comprising the amino acid sequence of atumor antigen peptide derived from said tumor antigen.
 18. The method asclaimed in claim 16, wherein the agent further comprises a detectablelabel.
 19. A diagnostic test kit which comprises an agent which bindsspecifically to (i) a nucleic acid which codes for a peptide comprisingthe amino acid sequence of a tumor antigen, (ii) a peptide comprisingthe amino acid sequence of a tumor antigen or of a tumor antigen peptidederived from said tumor antigen, (iii) an antibody which binds to apeptide comprising the amino acid sequence of a tumor antigen or of atumor antigen peptide derived from said tumor antigen, (iv) a T cellthat recognizes a peptide comprising the amino acid sequence of a tumorantigen or of a tumor antigen peptide derived from said tumor antigenand/or (v) a cell which presents a peptide comprising the amino acidsequence of a tumor antigen peptide derived from a tumor antigen,wherein said tumor antigen comprises an amino acid sequence encoded by anucleic acid which comprises the nucleic acid sequence according to SEQID NO: 1 of the sequence listing or a variant of said nucleic acidsequence and said tumor antigen peptide comprises an amino acid sequencesubstantially corresponding to the amino acid sequence of a fragment ofsaid tumor antigen, wherein the agent preferably further comprises adetectable label.
 20. An agent which binds to a peptide comprising theamino acid sequence of a tumor antigen or of a tumor antigen peptidederived from said tumor antigen, wherein said tumor antigen comprises anamino acid sequence encoded by a nucleic acid which comprises thenucleic acid sequence according to SEQ ID NO: 1 of the sequence listingor a variant of said nucleic acid sequence and said tumor antigenpeptide comprises an amino acid sequence substantially corresponding tothe amino acid sequence of a fragment of said tumor antigen, wherein theagent preferably is an antibody, more preferably a monoclonal, chimeric,human or humanized antibody, a fragment of an antibody or a syntheticantibody.
 21. A conjugate between an agent as claimed in claim 20 and atherapeutic effector moiety or a detectable label.
 22. Thepharmaceutical composition as claimed in any of claims 1, 3, or 5,wherein the tumor antigen comprises the amino acid sequence according toSEQ ID NO: 2 of the sequence listing or a variant of said amino acidsequence.
 23. The pharmaceutical composition as claimed in claim 10,wherein the tumor disease is selected from the group consisting of coloncancer, gastric cancer, metastatic colon cancer, and metastatic gastriccancer.
 24. The method as claimed in claim 11, wherein the tumor antigencomprises the amino acid sequence according to SEQ ID NO: 2 of thesequence listing or a variant of said amino acid sequence.
 25. Themethod as claimed in any of claim 12, 13, or 14, wherein the tumorantigen comprises the amino acid sequence according to SEQ ID NO: 2 ofthe sequence listing or a variant of said amino acid sequence.
 26. Thediagnostic test kit as claimed in claim 19, wherein the tumor antigencomprises the amino acid sequence according to SEQ ID NO: 2 of thesequence listing or a variant of said amino acid sequence.
 27. The agentas claimed in claim 20, wherein the tumor antigen comprises the aminoacid sequence according to SEQ ID NO: 2 of the sequence listing or avariant of said amino acid sequence.
 28. The conjugate as claimed inclaim 21, wherein the tumor antigen comprises the amino acid sequenceaccording to SEQ ID NO: 2 of the sequence listing or a variant of saidamino acid sequence.
 29. The method as claimed in claim 11, wherein thetumor disease is selected from the group consisting of colon cancer,gastric cancer, metastatic colon cancer, and metastatic gastric cancer.30. The method as claimed in claim 12 or 14, wherein the tumor diseaseis selected from the group consisting of colon cancer, gastric cancer,metastatic colon cancer, and metastatic gastric cancer.